Battery converter

Amp Hours to Watt Hours Calculator

Use the simple formula Wh = Ah x Volts. Enter amp-hours and battery voltage to convert Ah to Wh, estimate usable energy, and see a quick runtime example.

Quick resultRun estimate

Formula: Wh = Ah x Volts. A 100Ah 12V battery stores about 1,200Wh before reserve.

Inputs

Planning assumptions

Amp hours to watt hours formula

Watt-hours = Amp-hours x Volts

Multiply the battery's amp-hour rating by its nominal voltage. A 100Ah 12V battery is 1,200Wh. A 100Ah 24V battery is 2,400Wh.

Amp-hours (Ah)Battery capacity in amp-hours.Battery volts (V)Use nominal voltage: common examples are 12V, 24V, or 48V.Usable percentUsable depth after reserve. Lithium can often use more than lead-acid.Output efficiency percentUsed only for the optional runtime estimate; match the DC or inverter path.Example load wattsOptional runtime example after usable reserve.

Use this as a planning estimate

Small solar and backup-power estimates depend on real device draw, temperature, battery age, sun, shade, and product limits. Use the result to narrow a shopping range, then verify exact specs before buying.

Common examples

Quick conversions people search for

Example

50Ah 12V battery

50Ah x 12V = 600Wh before reserve.

Example

100Ah 12V battery

100Ah x 12V = 1,200Wh before reserve.

Example

200Ah 12V battery

200Ah x 12V = 2,400Wh before reserve.

Example

100Ah 24V battery

100Ah x 24V = 2,400Wh before reserve.

Example

100Ah 48V battery

100Ah x 48V = 4,800Wh before reserve.

Example

Runtime example

At 960Wh after reserve, 90% output efficiency, and a 50W load, the estimate is about 17.3 hours.

Planning notes

What this calculator is checking

Runtime

Power Station Runtime Calculator

Use watt-hours to estimate how long a device will run.

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Sizing

Power Station Size Calculator

Turn device watts and hours into a practical battery size.

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Guide

Amp-Hours to Watt-Hours Battery Math

Read the plain-language guide behind the calculator.

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Formula

Ah x V = Wh

Amp-hours by themselves do not tell you stored energy. Voltage is the missing piece.

12V example

100Ah at 12V is about 1,200Wh

That same 100Ah rating at 24V is about 2,400Wh, and at 48V it is about 4,800Wh.

Usable

Stored is not always usable

Reserve, inverter losses, cold weather, and battery limits reduce practical output.

Solar recharge time calculator

Check whether a panel can refill the battery within your usable sun window.

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FAQ

Common questions

Question

How do you convert amp hours to watt hours?

Multiply amp-hours by volts. The formula is Wh = Ah x V.

Question

How many watt hours is a 100Ah 12V battery?

A 100Ah 12V battery stores about 1,200Wh before reserve or inverter losses.

Question

How many watt hours is a 200Ah 12V battery?

A 200Ah 12V battery stores about 2,400Wh before reserve or inverter losses.

Question

Why are amp-hours misleading by themselves?

Amp-hours do not include voltage. A 100Ah 12V battery and a 100Ah 24V battery have very different stored energy.