How to Compute Drive Writes Per Day (DWPD)

Drive Writes Per Day (DWPD) calculations allow us to use the TBW specification of a drive to calculate the number of times the user capacity of a drive can be written per day over the warranty period (or a different number of years), based again upon the JEDEC workload used to specify the TBW.1

Drive Writes Per Day =

TBW of an SSD in TB * 1000

365 Days * Number of Years * SSD User Capacity in GB


For a 1.8TB DC400 SSD with a 5-year limited warranty, the calculation would be

Drive Writes Per Day =

1432TB * 1000

365 Days * 5 * 1800GB


= 0.43 or 43% of the drive capacity per day (that’s 774GB)