SSD endurance calculator: TBW, DWPD and lifespan
Every SSD can only be written a certain number of times. Enter the TBW rating and how much you write each day to see how many years the drive should last, and what that means in drive writes per day.
What TBW means
An SSD stores data in flash cells that wear slightly each time they are rewritten. Manufacturers describe how much wear a drive is designed for with a TBW figure, or terabytes written. A drive rated for 600 TBW is covered for that much data written over its life, as long as it is within the warranty period. The rating is a conservative guarantee, and many drives keep working well beyond it, but it is the figure the maker will honour.
The calculator divides the rating by the data you write each day to estimate how long it takes to use up the allowance. At 50 gigabytes a day, 600 terabytes lasts about 33 years, far longer than the drive is likely to be in service.
Lifespan at common ratings and write rates
Years until the rated TBW is used up. These are warranty-style figures, not predictions of failure.
| Rating | 25 GB a day | 50 GB a day | 150 GB a day |
|---|---|---|---|
| 150 TBW | 16.4 years | 8.2 years | 2.7 years |
| 300 TBW | 32.9 years | 16.4 years | 5.5 years |
| 600 TBW | 65.8 years | 32.9 years | 11.0 years |
| 1200 TBW | 131.5 years | 65.8 years | 21.9 years |
Drive writes per day
Another way to describe endurance is drive writes per day, or DWPD. It tells you how many times you can fill the whole drive every day for the length of the warranty. It is found by dividing TBW by the capacity and the number of days in the warranty. A 1 terabyte drive rated for 600 TBW with a five year warranty works out at about 0.33 DWPD, which means you could write a third of the drive every single day.
Consumer drives are usually between 0.2 and 0.6 DWPD, while server drives can be several times higher. For home use the figure is almost always more than enough, because most people write a few tens of gigabytes per day at most.
How much do games actually write?
Installing a game writes its full size once, and patches write more. After that, most games mainly read from the drive and write only small saves, caches and shader files. Video recording, large downloads, editing and scratch files write far more. If you capture gameplay all the time, your daily writes could be hundreds of gigabytes, and it is worth checking your drive health tool.
Faster drives help loading times, which you can estimate with the game load time estimator. To plan recording storage, use the recording size calculator.
How to use the sSD endurance calculator
- Find the TBW rating and capacity on the drive data sheet.
- Open your drive health tool and note total data written and how long the drive has been in use.
- Divide the data written by the number of days to get your daily writes.
- Enter the figures and read the lifespan and drive writes per day.
- Plan backups, whatever the result.
Common mistakes to avoid
- Treating the TBW rating as the exact moment the drive fails.
- Counting game installs as daily writes. They are mostly one-off.
- Skipping backups because the rating looks high.
Related tools and guides
Keep going with these: Game load time estimator, recording size calculator, download time calculator, PC build cost and wattage summary, best graphics cards guide.
Frequently asked questions
What does TBW mean on an SSD?
TBW stands for terabytes written. It is the total amount of data the maker guarantees the drive can handle over its warranty. A higher number means more endurance. It is a conservative figure, and many drives last beyond it, but it is the basis of the warranty.
How long will my SSD last?
Divide its TBW by your daily writes. A drive rated for 600 TBW with 50 gigabytes written a day should last over 30 years. Most users write far less than the rating allows, so the drive is more likely to be replaced for capacity or speed than for wear.
Do games wear out an SSD?
Not much. Installing a game writes its size once, and playing it mostly reads data. Patches, shader caches and saves add small writes. Heavy video recording, editing and large file moves write far more, so those are the activities to watch.
What is a good DWPD for a consumer SSD?
Consumer drives are often around 0.2 to 0.6 DWPD over a five year warranty, which is plenty for home use. Server and workstation drives can be much higher. If you write very little each day, even a low DWPD rating is more than enough.
How can I check how much I have written to my SSD?
Most drives report total data written through a health or SMART tool, often under names such as host writes or total bytes written. Note the figure and the date, then check again later to work out your daily average. A longer gap gives a steadier figure.
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