The calculation, without hidden assumptions
Ah measures electric charge while Wh measures energy. Voltage is the bridge between them. Keeping both directions on one page makes the assumption obvious: a 100 Ah battery does not have one fixed Wh capacity unless its voltage is also known.
How to use this calculator
Choose Ah → Wh or Wh → Ah.
Enter the known capacity and the nominal or relevant battery voltage.
Read the converted capacity, secondary units and reverse check before using the result in a runtime estimate.
Where people use it
- •Battery and UPS capacity comparisons
- •Solar and portable-power planning
- •Checking manufacturer capacity labels
Example: 100 Ah at 12 V
100 Ah × 12 V = 1,200 Wh, or 1.2 kWh. The same 1,200 Wh divided by 12 V returns 100 Ah.
What the result does not assume
- •Nominal voltage is a simplified energy conversion basis. Real battery voltage changes with state of charge and load.
- •Wh capacity does not directly equal usable energy; battery chemistry, discharge limits and conversion losses matter.
Frequently asked questions
Can I convert Ah to Wh without voltage?+
No. Energy depends on both charge and voltage.
Is a 100 Ah 12 V battery the same as 100 Ah 24 V?+
No. The 24 V battery has twice the nominal watt-hour energy at the same Ah rating.
Does this predict runtime?+
No. Use the Battery Runtime Calculator to add load, depth-of-discharge and efficiency assumptions.
Semantic next steps
Continue the calculation
These links move to a different input, formula or project stage rather than a keyword variation of this page.
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