SSD Lifespan Calculator (TBW and DWPD)

SSD makers state endurance as TBW (total terabytes that may be written under warranty) or DWPD (full drive writes per day over the warranty). This calculator turns either rating into years of use for your own workload — from an average daily figure or straight from the SMART counters — and converts between TBW and DWPD. For almost every home and office PC the answer is decades, and seeing the numbers helps when choosing a drive for heavy video, cache or database work.

How to use this tool

1. Choose TBW or DWPD and enter the rating from the drive's datasheet (DWPD also needs capacity and warranty years).
2. Enter your writes: an average GB per day, or SMART total host writes and power-on hours from a tool such as CrystalDiskInfo or smartctl.
3. Raise write amplification only if your workload is much heavier in small random writes than a typical PC.
4. Read the years until the rated TBW and the share already used.

Formula

years = TBW × 1000 ÷ (GB per day × WAF × 365); TBW = DWPD × capacity (TB) × 365 × warranty years

With SMART data the daily rate is host writes ÷ (power-on hours ÷ 24). Endurance used = host writes × WAF ÷ TBW. Decimal units are used throughout (1 TB = 1,000 GB). The rating already allows for the write amplification of a standard workload, so leave the extra factor at 1 unless you know yours is worse.

Example

A 1 TB drive rated 600 TBW in a PC that writes 50 GB a day lasts 600,000 ÷ (50 × 365) = 32.9 years before reaching its rating. A 2 TB data centre drive rated 0.3 DWPD for 5 years is good for 0.3 × 2 × 365 × 5 = 1,095 TBW. A drive whose SMART data shows 120 TB written in 8,760 hours averages 328.8 GB/day and has used 20% of 600 TBW, leaving about 4 years.