DWPD

DWPD, or drive writes per day, is an endurance metric used for solid-state drives (SSDs). It expresses the number of full drive writes that can be performed per calendar day over the drive’s advertised warranty period, assuming a uniform workload.

DWPD is related to, but distinct from, total bytes written (TBW). TBW is the total amount of data a drive is rated to write over its warranty, while DWPD normalizes TBW by drive capacity and warranty duration to provide a per-day endurance figure. The usual formula is DWPD ≈ TBW / (Capacity in TB × Warranty years × 365). For example, a 1 TB drive with a TBW rating of 365 TB for a 5-year warranty would have DWPD ≈ 365 / (1 × 5 × 365) = 0.2 DWPD, meaning the drive is expected to sustain about 0.2 full-drive writes per day over its warranty.

Typical DWPD values vary by use case. Consumer SSDs commonly list DWPD well below 1, often in the 0.05–0.3 range, reflecting lighter, consumer workloads. Enterprise and data-center drives may advertise higher DWPD, such as 1–3 DWPD or more, to accommodate heavier write workloads. Real-world endurance is influenced by workload pattern, wear leveling, overprovisioning, and idle time, not just the advertised rating.

DWPD is a useful comparative indicator when evaluating drives with similar capacities and warranty periods. It should be considered alongside TBW, warranty terms, and the expected workload profile to assess long-term reliability.