Battery Capacity (Ah to Wh)
Convert between Ah, Wh, mAh, runtime
📚 Learn more — how it works, FAQ & guide Click to expand
Learn more — how it works, FAQ & guide
Click to expand
Battery capacity calculator
Convert Ah, mAh, Wh. Estimate runtime with depth of discharge.
How to use this tool
- 1
Enter capacity + voltage
Battery rating from the label (e.g. 12V 100Ah).
- 2
Enter load
Device wattage the battery powers.
- 3
See runtime
Plus energy in Wh and usable runtime at DoD.
Frequently Asked Questions
Ah vs Wh
Wh = Ah × V. A 12V 100Ah battery holds 1200 Wh of energy. Wh is more useful for comparing across voltages.
Depth of discharge (DoD)
Lead-acid: 50% max (half the capacity). LiFePO4: 80-90%. Li-ion: 80%. Deeper discharge shortens battery life.
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