Two numbers, one rating. Convert drive writes per day to terabytes written (and back), see what each drive class is rated for, and work out how long a rating lasts at your own write volume.
Enter the drive’s capacity and warranty, then either rating. The other is calculated instantly, along with how long the rating lasts at your own write volume.
Quick answer
DWPD (drive writes per day) and TBW (terabytes written) are two ways of stating the same SSD endurance rating. TBW = DWPD × capacity in TB × 365 × warranty years. A 1 TB drive rated 0.3 DWPD for five years is good for about 550 TBW; a 3.84 TB enterprise drive rated 1 DWPD for five years is good for about 7,000 TBW.
DWPD answers the question: how many times per day could I overwrite this entire drive, every day, until the warranty runs out? A rating of 1 DWPD on a 3.84 TB drive means writing 3.84 TB every day for the warranty period. 3 DWPD means three full drive writes a day — about 11.5 TB a day on that same drive. Because it scales with capacity, DWPD is how datacenter buyers match a drive class to a workload without doing arithmetic for every size.
TBW is the total volume of data the manufacturer guarantees the drive will accept over its warranty, in terabytes. It is the number printed on consumer SSD spec sheets and the one you compare against the “total host writes” counter in SMART. Some enterprise sheets quote PBW (petabytes written) instead — 1 PBW is 1,000 TBW.
Compare TBW per terabyte of capacity when warranties differ. A drive with a three-year warranty shows a higher DWPD than a five-year drive with the identical TBW, which flatters it. For consumer drives, TBW is the practical number; for servers, DWPD tells you whether a drive class fits the workload. And remember both are warranty figures — drives typically write well past them before wearing out.
| Capacity | 0.3 DWPD | 1 DWPD | 3 DWPD |
|---|---|---|---|
| 500 GB | ~275 TBW | ~915 TBW | ~2,740 TBW |
| 1 TB | ~550 TBW | ~1,825 TBW | ~5,475 TBW |
| 2 TB | ~1,095 TBW | ~3,650 TBW | ~10,950 TBW |
| 3.84 TB | ~2,100 TBW | ~7,010 TBW | ~21,000 TBW |
| 7.68 TB | ~4,200 TBW | ~14,000 TBW | ~42,000 TBW |
Measure before you buy. Read the “Data Units Written” or “Total Host Writes”
value from your current drive's SMART data (CrystalDiskInfo on Windows, smartctl -a on Linux or macOS),
divide by the drive's age in days, and you have your real writes per day. Typical results:
Why some engineers dislike DWPD on spec sheets
DWPD assumes a steady, evenly spread workload and hides the effect of warranty length and write amplification. Small random writes to a nearly full drive can wear it several times faster than the same volume written sequentially. Treat DWPD as a class label, measure your real writes, and keep 10–20% of the drive free.
For the bigger picture — NAND types, wear levelling and what happens when a rating runs out — read SSD endurance & TBW explained, then compare drives by real cost per terabyte in the NVMe and enterprise rankings.
Consumer and prosumer NVMe drives sorted by real $/TB — check the TBW on the spec sheet.
Compare NVMe and enterprise SSDs by real cost per terabyte — no account, no email.
Open the $/TB rankings →