Technical guide
SSD Endurance Explained: TBW, DWPD, Warranty, NAND Writes, and Why Endurance Is Not Speed
Understand TBW, DWPD, warranty limits, host writes, NAND wear, and why endurance is separate from SSD speed.
SSD endurance utility
SSD TBW / DWPD Endurance Calculator
Convert an SSD endurance rating between TBW and DWPD using the drive capacity and the rating period. The calculator performs specification arithmetic only; it does not predict remaining life, failure date, health, reliability, or performance.
Interactive calculation
Convert the published endurance rating
Enter the capacity and rating period attached to the SSD specification, then convert TBW to equivalent DWPD or DWPD to equivalent TBW. The defaults are only an arithmetic example, not a typical SSD claim.
Decimal units only: 1 TB = 1,000 GB. Do not enter TiB while treating it as TB.
Use the specified endurance-rating period for the product. This is often the warranty period, but the exact manufacturer specification and warranty remain authoritative.
Equivalent rated endurance
0.329 DWPD
Specification conversion only. This is not a lifespan, health, reliability, or failure-date prediction.
- Rated writes per day
- 0.329 TB/day
- Rating period
- 1,825 days
- Entered total endurance
- 600 TBW
Formula convention: DWPD = TBW ÷ (capacity TB × years × 365); inverse TBW = DWPD × capacity TB × years × 365.
Interpretation boundary: the result converts two published endurance-rating formats. It does not estimate remaining NAND life, SMART health, write amplification, or when a drive will fail.
Calculation basis
The capacity and time period are part of DWPD
KIOXIA publishes the relationship directly: TBW = DWPD × SSD capacity in TB × specified lifetime in years × 365 days. Rearranging the same equation gives DWPD = TBW ÷ (capacity × years × 365).
This tool uses exactly 365 days per endurance-rating year. It does not substitute the average Gregorian year used by the electricity-cost calculator because the endurance references define their conversion with 365 days.
Capacity is entered in decimal terabytes: 1 TB = 1,000 GB. TBW and capacity therefore stay on the same decimal scale rather than silently mixing TB with TiB.
Interpretation
A rating conversion is not a wear forecast
TBW and DWPD describe rated write endurance over a stated period. They do not tell you how much data your system actually writes each day, when NAND will fail, or how an SSD performs in sequential or random workloads.
NVMe devices expose separate health information such as Percentage Used and Data Units Written. Those live counters are not replaced by this calculator, and manufacturer warranty conditions can use different limits or health attributes.
References
Formula, health, and warranty sources
These sources support the formula and the separation between rated endurance, live health information, and product-specific warranty conditions. They do not provide a hidden product database for this calculator.
01 · KIOXIA
SSD NAND endurance technical brief with TBW ↔ DWPD conversion formulas02 · Kingston Technology
Understanding SSD endurance: TBW and DWPD definitions and conversion03 · NVM Express
NVMe SMART health monitoring, Percentage Used, and Data Units Written04 · Samsung
Consumer SSD limited-warranty conditions and warrantied TBW limits
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