Battery Charging Time Calculator
Estimate constant-current charging time from capacity and state-of-charge change.
Capacity Ah and current A: 0.000001–1000000000; start and target state of charge: 0–100%, target ≥ start; supplied efficiency: 0.000001–100%. Constant current and fixed user-supplied efficiency only. No charging curve, voltage-stage taper, balancing, temperature or charger controls. Not a charging procedure or guaranteed completion time. Enter your own efficiency; there is no recommended default. Other starting values are editable arithmetic examples.
t(h) = Q(Ah) × (SOC₂ − SOC₁)/100 ÷ (I(A) × η(%)/100)
Estimated time (hours)
A QUICK WALKTHROUGH
How to use this tool
- Enter capacity and current, then starting and target state of charge.
- Enter your own efficiency, then calculate, copy or download.
Formula and limits
Capacity Ah and current A: 0.000001–1000000000; start and target state of charge: 0–100%, target ≥ start; supplied efficiency: 0.000001–100%. Constant current and fixed user-supplied efficiency only. No charging curve, voltage-stage taper, balancing, temperature or charger controls. Not a charging procedure or guaranteed completion time. Enter your own efficiency; there is no recommended default. Other starting values are editable arithmetic examples. t(h) = Q(Ah) × (SOC₂ − SOC₁)/100 ÷ (I(A) × η(%)/100)
Estimated time (hours)
Use your own charge efficiency; no default efficiency is recommended. The other starting numbers are editable arithmetic examples.
GOOD TO KNOW
Common questions
Does this evaluate a real component or circuit?
No. This is a nominal calculation from the inputs, not component selection or a safety assessment.
Are these a charging curve or a guaranteed completion time?
No. Current and efficiency are constant in this model; taper, balancing, temperature and charger controls are excluded.