Question 1

How do you convert amp-hours to kWh?

Accepted Answer

Multiply amp-hours by the battery's voltage, then divide by 1,000: kWh = Ah × V ÷ 1,000. For example, a 100 Ah battery at 12V is 1.2 kWh nominal. Usable energy is lower once you account for depth of discharge and efficiency.

Question 2

What's the difference between nominal and usable kWh?

Accepted Answer

Nominal kWh is the full Ah × V figure on the label. Usable kWh is what you can actually draw: nominal × depth of discharge × efficiency. A 1.2 kWh lead-acid battery at 50% DoD and 90% efficiency gives only about 0.54 kWh usable.

Question 3

What depth of discharge should I use?

Accepted Answer

Lead-acid batteries last longest at around 50% DoD. Lithium (LiFePO₄) typically tolerates 80–100%. Using the right DoD matters more than the raw amp-hours when you're sizing a real system, which is why this calculator includes it.

Question 4

How is runtime estimated?

Accepted Answer

Runtime ≈ usable Wh ÷ load watts. Enter a load and the calculator divides the usable energy by it. Real runtime is a bit shorter under high current draw (Peukert effect) and inverter losses, so treat it as an upper estimate.

Question 5

How do you convert kWh to amp hours?

Accepted Answer

Multiply kilowatt-hours by 1,000 and divide by the pack voltage: Ah = kWh × 1,000 ÷ V. Example: 5 kWh at 48 V is about 104 Ah. The voltage matters more than people expect: the same 5 kWh is 417 Ah at 12 V, which is why low-voltage battery banks need such heavy cabling.

Amp Hours to kWh Calculator and kWh to Ah

Batteries rated in watt-hours

Jackery Explorer 1000 v2

EcoFlow RIVER 3 Plus

Frequently asked questions

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Related converters

mAh ↔ Wh

Watts ↔ Amps

kW ↔ Amps

Volts ↔ Watts

Sources & standards