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watt hours to amp hours calculator

Watt Hours to Amp Hours Calculator

RV, solar, and battery systems often use Ah, but portable station specs use Wh. Convert between them with voltage visible.

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Voltage presets

Use the voltage printed on the battery label when available. mAh without voltage cannot be compared fairly.

Converted capacity

27.03 AhConverted capacity: 27.03 Ah

Ah = Wh / volts

Watt-hours100 Wh
Amp-hours27.03 Ah
Milliamp-hours27,027 mAh
Voltage3.7 V
Travel check: At or below 100 Wh, lithium-ion spare batteries are within the standard FAA PackSafe size limit, but airline, route, and damage-protection rules still apply. Check the FAA PackSafe lithium battery page and your airline before flying with spare batteries or power banks. Reviewed 2026-06.
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WattRunTime battery capacity conversion

Converted capacity27.03 Ah
ModeWh to Ah
Watt-hours100 Wh
Voltage3.7 V
Result27.03 Ah

WattRunTime battery capacity conversion

  • WattRunTime battery capacity conversion
  • Mode: Wh to Ah
  • Input: 100 Wh
  • Voltage: 3.7 V
  • Result: 27.03 Ah
  • Watt-hours: 100 Wh
  • Travel note: At or below 100 Wh, lithium-ion spare batteries are within the standard FAA PackSafe size limit, but airline, route, and damage-protection rules still apply.
  • Use the voltage printed on the battery label when available. mAh without voltage cannot be compared fairly.

At or below 100 Wh, lithium-ion spare batteries are within the standard FAA PackSafe size limit, but airline, route, and damage-protection rules still apply.

Use Wh to Ah for 12 V, 24 V, and 48 V systems

This direction is for RV, solar, and battery-bank planning where system voltage changes the amp-hour result.

Formula focus

Ah = Wh / V. A 1,200 Wh battery is 100 Ah at 12 V, 50 Ah at 24 V, and 25 Ah at 48 V.

Best use case

Use this when matching portable-station Wh specs to DC loads, solar controllers, or battery-bank language.

Power Station Capacity Runtime Guides

How To Convert Wh To Ah By Hand

Amp-hours depend on voltage, so the same watt-hour rating gives a different Ah number on each system voltage.

  1. Start with the energy rating in watt-hours (Wh) from the battery label or spec sheet.
  2. Find the voltage you will draw from: 12 V, 24 V, 48 V, or the value printed on the battery.
  3. Divide: Ah = Wh / V. The result is the amp-hour figure at that voltage.
  4. Sanity-check by multiplying back: Ah x V should return the original Wh.

12 V example

A 1,024 Wh rating on a 12 V system: 1,024 / 12 = about 85.3 Ah.

24 V example

The same 1,024 Wh on a 24 V system: 1,024 / 24 = about 42.7 Ah. Half the amp-hours, same stored energy.

Common System Voltages

Typical nominal voltages for reading Ah figures in context. Prefer the voltage printed on the battery label when it differs.

Swipe table sideways
Common System Voltages
Nominal voltageTypical use1,200 Wh equals
12 VCar and RV auxiliary batteries, small solar setups, many DC accessories100 Ah
24 VLarger RV and marine banks, some off-grid inverters50 Ah
48 VHome energy storage and larger off-grid systems25 Ah

Wh To Ah FAQ

Short answers to the arithmetic questions behind this conversion.

What is the formula for converting watt-hours to amp-hours?

Ah = Wh / V. Divide the watt-hour energy rating by the system voltage. For example, 600 Wh / 12 V = 50 Ah.

Why does the voltage matter?

Watt-hours measure energy; amp-hours measure charge. The same energy moves fewer amps at a higher voltage, so 1,200 Wh is 100 Ah at 12 V but only 25 Ah at 48 V.

How do I convert amp-hours back to watt-hours?

Multiply instead of dividing: Wh = Ah x V. A 100 Ah battery at 12 V stores 1,200 Wh.

Which voltage should I use in the conversion?

Use the nominal voltage printed on the battery label. If a label lists both Wh and Ah, you can recover its assumed voltage with V = Wh / Ah.

Are Wh and Ah interchangeable ratings?

No. Ah alone does not say how much energy a battery stores; it only becomes comparable once multiplied by voltage. Wh is the unit to use when comparing batteries at different voltages.