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MTBF Formula (Table of Contents)

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MTBF Formula

MTBF is the usual term mainly used in the field of manufacturing industries. It is the average time taken between the two failures. That is the start of last uptime to start of follow up failure. This is predominantly used to access system reliability and compare different system designs. In the current world, this is used in software industries as well for a similar type of prediction.

A formula for MTBF (Mean Time Between Failure) is –

MTBF = ∑ (TOT) / F


TOT = Total Operational Time which is calculated by using the below formula

TOT = ∑ (Start of Downtime after last Failure – Start of Uptime after last Failure)

F = Number of Failures

FR = 1 / MTBF

These measures are generally very helpful in finding a failure rate which can be a preventive measure of many systems. High MTBF value means that the system is too good for operational.

Examples of MTBF Formula (With Excel Template)

Let’s take an example to understand the calculation of MTBF formula in a better manner.

You can download this MTBF Template here – MTBF Template

MTBF Formula – Example #1

The overall operating hours of a system is 10 hours per day. But there are two failures with the downtime of 1 hour and 2 hours. Calculate the MTBF and Failure rate.


Total Down Time is calculated as:

Total Down Time = 1 +2

Total Down Time = 3 hours

Since there are 2 failures of 1 and 2 hours, overall downtime for this system is 3 hours.

TOT is calculated using the formula given below

TOT = ∑ (Start of Downtime after last Failure – Start of Uptime after last Failure)

TOT = 10 – 3

TOT = 7 hours

Hence the overall operational time is 7 hours.

MTBF is calculated using the formula given below

MTBF = ∑ (TOT) / F

MTBF = 7 / 2

MTBF = 3.5 hours

Hence the system will be down for every 3.5 hours that will result in a loss to the organization.

Failure Rate is calculated using the formula given below

Failure Rate = 1 / MTBF

Failure Rate = 1 / 3.5

Failure Rate = 0.28571

MTBF Formula – Example #2

There is a Bank bazaar website. Its availability is 24 hours per day. However, the site is not available during 12-1 PM IST and also another incident during 3-3.30 am IST. What would be the MTBF for this website?


Total Down Time is calculated as:

Total Down Time = 1 +0.5

Total Down Time = 1.5 hours

Since there are 2 failures of 1 and 0.5 hours, overall downtime for this system is 1.5 hours.

TOT is calculated using the formula given below

TOT = ∑ (Start of Downtime after last Failure – Start of Uptime after last Failure)

TOT = 24 – 1.5

TOT = 22.5 hours

Hence the overall operational time can be calculated is 22.5 hours.

MTBF is calculated using the formula given below

MTBF = ∑ (TOT) / F

MTBF = 22.5 / 2

MTBF = 11.25 hours

Hence the system will be down for every 11.25 hours that will result in a loss to the organization.

Failure Rate = 1 / MTBF

Failure Rate = 1 / 11.25

Failure Rate = 0.08889

Failure rate per hour would be 0.08889.

Hence the system is more stable!!


Below is the step by step approach for attaining MTBF Formula.

Step 1: Note down the value of TOT which denotes Total Operational Time. It can be calculated by deducting the start of Uptime after the last failure from the start of Downtime after the last failure. Simply it can be said the productive operational hours of a system without considering the failure duration.

T = ∑ (Start of Downtime after last failure – Start of Uptime after last failure)

Step 2: Note down the value of F. It is the number of failures occurred in a system.

Step 3: Finally MTBF can be calculated using the above formula.


Step 4: Failure Rate is just the reciprocal value of MTBF. Thus the formula is,

FR = 1 / MTBF

Relevance and Uses of MTBF Formula

MTBF value simply tells about a product’s survival time. It is very important in Hardware product Industries rather than consumers. It is simply the number of failures occurring per hour. Consumers mostly go with a price-driven approach hence do not mind much about MTBF. When it comes to industries, based on MTBF values only systems with different designs are compared. This value tells about Reliability, stability, and performance of a system. Because a system’s performance relies on its stability. How often it gets a failure and how productive it is. Low MTBF always denotes that the system is not stable and not much operational. And for critical products such as Airplanes, safety equipment assets, inverters, generators, etc., performance and stability are very important. In this case, MTBF is the indicator of Performance expected from a specific system and also a metric for reliability and acts as a tool at the stage of design and production of hardware. This metric is simply known as average life expectancy. The wrong predictions of a product’s stability lead to poor designs and performance of systems. This says how often a product to be maintained to avoid breakdowns. An also MTBF is a current status indicator of performance in plant maintenance as a preventive maintenance schedule.

MTBF Formula Calculator

You can use the following MTBF Calculator


(TOT) F MTBF Formula   MTBF Formula =


(TOT) = F


= 0


Recommended Articles

This has been a guide to MTBF Formula. Here we discuss how to calculate MTBF along with practical examples. We also provide MTBF calculator with downloadable excel template. You may also look at the following articles to learn more –

You're reading How To Calculate Mean Time Between Failure?

How To Change Time Or Time Zone On Android

By default, Android devices rely on the network providers to relay the time correctly. Andriod devices also rely on the network provider, to determine which time zone you are in. Your network provider tracks your location and updates your time zone when you travel. This is how your device mostly displays the correct time. 

If your service provider glitches or you lost your network when traveling, you may get the incorrect time displayed. Your device does not have to rely on your network provider to tell the time. It can also be set to different time zones, without your location being tracked. To do this, you can manually set your time and time zone. Here is how you can manually change the time and time zone of your Android device.

How to change the time manually on Android

You can change time on your Android device either through the Settings app or through the Clock app. Let’s take a look at both the procedures.

Method #1: Change time via the Clock App

Open the Clock app on your device and tap on the ‘3-dot’ menu icon in the top right corner. 

Tap and select ‘Settings’. 

Now tap on ‘Change date & time’. 

Disable the toggle for ‘Use network-provided time’ at the top. 

Tap on ‘Time’ which shouldn’t be greyed out anymore. 

Set your desired time by dragging around the highlight on the clock.

You can also tap the keyboard icon to manually enter the correct time.

Tap on ‘Ok’ to set the manually entered time. 

Additionally, tap and set the correct ‘Date’ in case it is wrong to keep your clock in check. 

And that’s it! You will have now set your time manually on your Android device. 

Method #2: Change time via the Settings App

To change your device’s time manually, first, open your device setting.

Scroll down and tap on System. 

Tap on Date & time. 

Note: On Samsung phones, the Date & time settings can be found by opening General management and not System settings. Additionally, depending on your OEM, the location for this option can be slightly different. 

Switch off “Use network-provided time”, using the toggle on the right side of the screen. 

This will allow you to edit the time. Tap on Time. 

Change the time and tap on OK. 

This will change the time displayed on your device. 

How to change the time zone manually on Andriod

When changing time manually there is the risk of setting an incorrect time. To reduce the risk of being off-time, manually set the time zone of your device. Setting the time zone, allows your device to not rely on the network provider. You can either set a manual time zone using the Settings app or the Clock app. Let’s take a quick look at both of these methods. 

Method #1: Via the Clock app

Open the clock app and tap on the ‘3-dot’ menu icon. 

Now tap and select ‘Settings’. 

Tap on ‘Change date & time’. 

Now turn off the toggle for ‘Use network-provided time zone’. 

Tap on ‘Time Zone’. 

Tap on ‘Region’ to select a region manually. 

And that’s it! Your time zone will now be automatically changed based on the region selected by you.

If you find the ‘Time Zone’ section greyed out, do not worry as you only get to select this if your selected region has multiple timezones. 

Method #2: Via the Settings app

Open the settings of your device and tap on System. 

To open time settings, tap on the Date & time option. 

Slide off the toggle on the right side of the screen, to disable “Use network-provided time zone”. 

This enables you to select the time zone manually. 

Tap on Time zone. 

Tap on Region. 

From the list, you can scroll or search for the region for your time zone. Select the Region. 

If the region has multiple time zones, you will be shown a list of them. From the list, select the time zone you want to set on your device. 

This will change the time on your device. 

Note: The time you set manually always overrides the time zone. This means that if you set the device’s time manually, it will display that time irrespective of the set timezone. If you want your device to show your time zone’s time, then switch “Use network-provided time” back on and set the time zone manually. 

How to set a home clock on Andriod when traveling

When you travel, your phone can help you keep track of the time at your destination as well as back home. 

Open the Clock app on your Andriod device. 

Tap on the settings icon. 

Turn on the Automatic Home Clock feature, by sliding on the toggle on the right side. 

This will allow you to select Home Time Zone. Tap on Home Time Zone. 

Scroll through the list of time zones, or use the search option, to find the time zone of your home. Select that time zone. 

The time zone will be set as your home time zone. 

Now, when you travel you can check your home time zone. To do this go to the Clock app and tap on world clock. 

This is how you can manually change the time on your Andriod device and set a home time zone as well. 


How To Calculate Age In Excel Using Formulas + Free Calculator Template

Watch Video – How to Calculate Age in Excel (in Years, Months, and Days)

Using a combination of Excel functions and the date of birth, you can easily calculate age in Excel. You can either calculate the age till the current date or between the specified period of time.

The technique shown here can also be used in other situations such as calculating the duration of a project or the tenure of the service.

In this tutorial, you’ll learn how to calculate age in Excel in:

The number of years elapsed till the specified date.

The number of Years, Months, and Days elapsed till the specified date.

You can also download the Excel Age Calculator Template.

Suppose you have the date of birth in cell B1, and you want to calculate how many years have elapsed since that date, here is the formula that’ll give you the result:


If you have the current date (or the end date) in a cell, you can use the reference instead of the TODAY function. For example, if you have the current date in cell B2, you can use the formula:


DATEDIF function is provided for the compatibility with Lotus 1-2-3.

One of the things that you’ll notice when you use this function is that there is no IntelliSense available for this function. No tooltip appears when you use this function.

This means that while you can use this function in Excel, you need to know the syntax and how many arguments this function takes.

If you’re interested in knowing more about DATEDIF function, read the content of the box below. If not, you can skip this and move to the next section.

Syntax of DATEDIF function:

=DATEDIF(start_date, end_date, unit)

It takes 3 arguments:

start_date: It’s a date that represents the starting date value of the period. It can be entered as text strings in double-quotes, as serial numbers, or as a result of some other function, such as DATE().

end_date: It’s a date that represents the end date value of the period. It can be entered as text strings in double-quotes, as serial numbers, or as a result of some other function, such as DATE().

unit: This would determine what type of result you get from this function. There are six different output that you can get from the DATEDIF function, based on what unit you use. Here are the units that you can use:

“Y” – returns the number of completed years in the specified time period.

“M” – returns the number of completed months in the specified time period.

“D” – returns the number of completed days in the specified period.

“MD” – returns the number of days in the period, but doesn’t count the ones in the Years and Months that have been completed.

“YM” – returns the number of months in the period, but doesn’t count the ones in the years that have been completed.

“YD” – returns the number of days in the period, but doesn’t count the ones in the years that have been completed. 

You can also use the YEARFRAC function to calculate the age in Excel (in years) in the specified date range.

Here is the formula:


The YEARFRAC function returns the number of years between the two specified dates and then the INT function returns only the integer part of the value.

NOTE: It’s a good practice to use the DATE function to get the date value. It avoids any erroneous results that may occur when entering the date as text or any other format (which is not an acceptable date format).

Also read: How To Calculate Time In Excel

Suppose you have the date of birth in cell A1, here are the formulas:

To get the year value:


To get the month value:


To get the day value:


Now that you know how to calculate the years, months and days, you can combine these three to get a text that says 26 Years, 2 Months, and 13 Days. Here is the formula that will get this done:

=DATEDIF(B1,TODAY(),"Y")&" Years "&DATEDIF(B1,TODAY(),"YM")&" Months "&DATEDIF(B1,TODAY(),"MD")&" Days"

Note that the TODAY function is volatile and its value would change every day whenever you open the workbook or there is a change in it. If you want to keep the result as is, convert the formula result to a static value.

Excel Functions Used:

Here is a list of functions used in this tutorial:

DATEDIF() – This function calculates the number of days, months, and years between two specified dates.

TODAY() – It gives the current date value.

YEARFRAC() – It takes the start date and the end date and gives you the number of years that have passed between the two dates. For example, if someone’s date of birth is 01-01-1990, and the current date is 15-06-2024, the formula would return 26.455. Here the integer part represents the number of years completed, and the decimal part represents additional days that have passed after 26 years.

DATE() – It returns the date value when you specify the Year, Month, and Day value arguments.

INT() – This returns the integer part of a value.

You May Also Like the Following Excel Tutorials:

How To Take Astrophotography Photos And Time

Pixel phones are known for their excellent cameras and computational photography. But AI improvements aren’t exclusive to general shots. Google’s algorithmic magic also makes interesting features like astrophotography mode possible. Shooting in astrophotography mode isn’t as easy as picking a mode and shooting, though. It’s a bit of a hidden feature, so we’re creating this tutorial for shooting astrophotography photos and time-lapses on Pixel phones.

Read more: Here’s what Google’s astrophotography can do


You can shoot astrophotography photos and time-lapses by launching the Camera app and going to Night Sight. Make sure the phone is completely still and the subject is dark. After a few seconds, the Moon shutter button should turn into a Stars shutter button. This means astrophotography mode is on. Shoot the image, make sure the phone doesn’t move in the process, and you’ll get an excellent astrophotography photo.


Supported devices

Enable astrophotography mode in the settings

How to shoot in astrophotography mode

Ways to improve your astrophotography photos

Editor’s note: All instructions in this tutorial were assembled using a Google Pixel 7 running Android 13. Keep in mind things might be a bit different depending on your device and its software version.

Enable Astrophotography mode in the settings

Astrophotography mode is a bit of a hidden feature. You can’t just tap on the shooting modes and pick it. This is why you should enable the feature before you drive off to the mountains.

How to enable Astrophotography mode:

Open the Camera app.

Go into Night Sight mode.

Tap on the Settings arrow down button on the top of the screen.

Make sure the Astrophotography option is set to Auto.

If, for any reason, you want to disable the feature, you can do that here too.

Shooting in astrophotography mode:

Go to a dark area with a nice sky view, preferably away from city lights. It also works on photos without a sky showing, though. It’s pretty much an enhanced night mode.

Prop your phone up in a way that it doesn’t move. You can use a tripod, or lean the phone against anything.

Open the Camera app.

Go into Night Sight mode.

Leave the phone still.

After a few seconds, the Moon shutter button will change into a Stars shutter button. This signifies a switch to astrophotography mode.

Tap on the Stars shutter button, and the phone will start shooting the astrophotography

How to get astrophotography time-lapse:

Shoot a photo in astrophotography mode using a Pixel 4 or newer.

The phone will automatically capture a time-lapse of the night sky when shooting in astrophotography mode. You can find it in the Photos app.

Ways to improve your astrophotography photos

Dhruv Bhutani / Android Authority

OK, so now you know how to shoot in astrophotography mode. Using the feature and taking a good photo are two completely different things, though. Let’s give you some tips to get the best possible results when using your Pixel phone to shoot astrophotography images.

Use a timer or remote shutter

Consider getting a tripod!

Edgar Cervantes / Android Authority

We know tripods can get pricey, and are cumbersome to carry around. These are usually tools only very serious photographers use, but we can tell you a tripod will make a huge difference. While leaning a phone against something works, it doesn’t offer the flexibility a tripod will. With a tripod, you can move the phone lower, or higher, and pan the head as you wish. We have a dedicated post with our favorite tripods. It comes with all kinds of options, from portable tripods to heavy-duty ones, so there’s something for everyone in there. If all you care about is smartphone tripods, though, we also have a list of the best phone tripods around.

You’ll also want a smartphone tripod adapter. There are plenty of them on Amazon, but if you want a recommendation, I like this Manfrotto one.

Grab a power bank

Rita El Khoury / Android Authority

Shooting photos for multiple minutes is a sure way to ensure your phone dies quickly. This is no good news, especially if you’re out in the wild, away from the city, and the convenient outlets it offers. You’ll need a good portable battery. Check out our list of the best portable batteries to find a good one.

This mode essentially works as an enhanced night mode. It shoots multiple long-exposure images, stitches them together, and uses machine learning to process the image and bring out all possible detail while keeping quality as good as possible.

You can shoot in astrophotography mode using Pixel 3 or newer Pixel phones.

Not really. For starters, the Pixel device won’t activate astrophotography mode if it notices any movement. You would need to be so still that the phone believes it’s not being handheld.

Astrophotography mode is part of Night Sight. You can find the settings and options in that section.

How To Transfer Files Between Iphone And Mac

Last Updated on May 17, 2023

One of the main features of the Apple ecosystem is the file transfer between linked devices. You can easily transfer files from your iPhone to your Mac with the help of iCloud services. There are many reasons why you might want to transfer files between these devices and there is a solution that will surely work for you.

Luckily Apple offers quick procedures and you no longer need USB cables or traditional data transfer methods. Continue reading as we present you with 6 ways to transfer files between iPhone and Mac.

Now Read – What Type Of Mac Do You Need?


Syncing Between Your iPhone and Mac

You can directly transfer files between these devices by syncing them. Both your iPhone and Mac have to be connected to the same Wi-Fi network in order for this method to work. All you have to do is set up Wi-Fi syncing from your Mac and select the settings based on your own needs. When your iPhone and Mac are connected, you can select the iPhone from the laptop in order to sync it.


Use Dropbox


Use iCloud Drive





Apple has developed a file-sharing system that allows you to quickly transfer files between their devices. When you enable AirDrop on your iPhone, you are able to send files between any other iOS or Mac devices.

This can be done either through Bluetooth or Wi-Fi connection, and you have the choice of picking the fastest one. You can AirDrop contacts directly without having to manually direct your files to them. The flexibility is high, so you might want to transfer files using AirDrop for your convenience.

To do this following these steps:-



How to use Airdrop

Open ”Control Center” on your iPhone and make sure that both Bluetooth and Wi-Fi are turned on.



Tap Airdrop

Tap on ”AirDrop” and make your smartphone visible and discoverable by other devices.



Connect to the same network

Next, turn on this function on your Mac by accessing it from the ”Finder”. Switch Bluetooth and Wi-Fi on but make sure to connect to the same network.



Start file sharing

Once both of these devices have enabled AirDrop and can be discovered by anyone, you will be able to see them and create a private connection for file sharing.


iTunes File Sharing

This is another app that allows quick and easy file sharing.



Connect your iPhone to your computer and open iTunes.

Connect your iPhone to your computer using one of the methods presented above. Continue by accessing the iTunes app on your Mac and you will be able to see your smartphone there as well.



Choose documents to transfer.

At this point, file transfer becomes an easy thing to do. Choose the documents that you want to share and you can transfer them instantly.

Access the iTunes app from the receiving device, and you will find your files there.

Final Thoughts

As you can see, all of these 6 methods are effective and will get the job done quickly. Try the one that is available for you and stick with it in the long-term.

How To Hack Screen Time Passcode On Iphone 2023

Due to the increased and uncontrolled usage of smartphones, Apple introduced Screen Time Passcode to control and restrict screen time. It prevents the excess usage of the application and the device and keeps track of all your activities.

This passcode is different from the passcode you use to unlock the device. Therefore, most of the time, the users forget this passcode after setting it. Once you forget the passcode, you cannot use the device as you like and change various settings. It creates various issues, so the users try to find ways to get rid of it.

In this article, we will tell you how you can bypass the screen time passcode without the Apple ID and password. We will share different ways that can solve your problem.

Best 8 Methods to Hack Screen Time on iPhone

Step 1: Download Tenorshare 4uKey on your computer. It is available for Windows and Mac.

Step 3: Connect your iPhone to the computer.

Your device will be recognized automatically. But if not, unlock your device and tap Trust.

Also read:

7 Best Woocommerce Plugins to boost your Store you must know

Step 5: Now, you need to disable Find My iPhone on your device. Follow the instructions on the screen.

Step 6: The software will start removing the passcode. Once the passcode is removed, the device will restart. While setting up the device, you need to select Don’t Transfer Apps and Data and Set Up Later for Screen Time.

2. How to Bypass Screen Time Limits via Uninstall and Reinstall Apps

It is a screen time passcode hack. If you are allowed to remove and reinstall the application, you can do that to bypass screen time restrictions.

3. How to Hack Screen Time Passcode via Watch YouTube on iMessages

You can watch YouTube even if there is a screen time restriction. For this, you need to use iMessage, and the Screen Time feature won’t be able to detect that you are using YouTube.

Step 1: Go to iMessage and tap on the message area.

Step 2: Tap Applet’s icon and then tap on the YouTube icon. You can now see YouTube videos directly on your device.

Also read:

Top 10 Helpful GitHub Storage For Web Developers

4. Change the Phone Time to Overcome Apps Restrictions

Another way to trick Screen Time restrictions is by changing the time of the device. It will remove the screen time restrictions for some time, and then you can change the time and settings again.

5. How to Turn Off Screen Time without a Passcode via Send Message to Siri

You can use this hack to bypass screen time on your iPhone to send messages. But keep in mind that this hack is only for messaging. Another condition for this hack to work is that you need to enable Siri on your device.

Step 1: On your device, ask Siri to send a message.

Step 2: Siri will ask you for the recipient’s name. Then, you can say your message.

Step 3: Once you say “Send”, the message will be sent to the recipient.

6. Use Recording Video to Hack Screen Time

This method is not bypassed or hack the screen time passcode. Instead, it is for remembering or recalling the passcode if you forget. You can use the screen recording feature to record the screen. It will help you recall the passcode you have entered.

Step 1: Swipe up on the main screen.

Step 3: It will start recording the screen. You can type the screen time passcode and then end the recording. The video will be saved to the Gallery.

7. Hack Screen Time by Factory Reset

You can remove the screen time passcode by factory reset, but this is not the option that you like to choose in the first place. It will remove all your data and settings; however, if you have created a backup, you can restore it.

Step 1: Go to Settings.

Step 3: Tap Erase All Content and Settings.

Now, confirm it, and your device will be set to the factory settings like a brand-new iPhone.

8. Send Messages via Use the Contacts App

If you are looking for how to hack screen time and send messages, this is another option you can go with. You can send messages using the Contact application.

Step 1: Go to the Contacts app and select the contact to which you want to send a message.

Step 2: Tap Message, and it will bypass Screen Time restrictions and take you to the message application.

The Bottom Line

We have discussed how to hack the screen time limit and remove the passcode. You can try any of these methods that you think are suitable for your case. If you want to save time and bypass the screen time passcode, you should try Tenorshare 4uKey. It is the best software that removes the passcode in no time. Your data remains intact, and the passcode is removed without entering your Apple ID and password. Beginners can easily follow the simple steps and remove the passcode without any hassle.

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