BEHIND THE RESULT
How the calculation works
C-rate = current A ÷ rated capacity Ah. Current A = C-rate × Ah. Capacity Ah = A ÷ C-rate.
1C describes a current numerically equal to the Ah rating. A nominal one-hour relationship assumes ideal constant current; real usable time depends on battery behavior.
A worked example
50 A through a rated 100 Ah battery is 0.5C. A specified 0.5C rate on a 200 Ah battery corresponds to 100 A mathematically.
What this estimate can’t tell you
C-rate is a ratio, not permission to charge or discharge at that rate. Only the battery and BMS manufacturer can specify permitted current, temperature and protection limits.
Sources & methodology
Formulas are derived from the units shown. Read our methodology or report a correction. Sources reviewed 2026-11-01.