Enter the voltage and either capacity (Ah/mAh) or energy (Wh/kWh) to convert the other.
Common Mistakes Quick tips
- Leaving voltage blank or using the wrong unit; convert mV to V when needed.
- Entering values in both Capacity and Energy; fill exactly one of them.
- Confusing amps (A) with amp-hours (Ah); Ah is capacity, not instantaneous current.
- Mixing Wh and kWh or using pack voltage incorrectly; use nominal system voltage and remember 1 kWh = 1000 Wh.
When to Use This Calculator
- Sizing batteries from energy needs (kWh) or estimating stored energy from capacity (Ah).
- Comparing battery packs across different voltages (12 V, 24 V, 48 V, etc.).
- Converting datasheet ratings for solar, RV, UPS, and backup power planning.
Input Definitions
- Voltage — system/battery voltage in V or mV (1 V = 1000 mV).
- Capacity — amp-hours (Ah) or milliamp-hours (mAh), where 1000 mAh = 1 Ah.
- Energy — watt-hours (Wh) or kilowatt-hours (kWh), where 1 kWh = 1000 Wh.
- Conversions — Wh = Ah × V; kWh = Ah × V ÷ 1000; Ah = (kWh × 1000) ÷ V.
Ah to kWh Formula
The following formulas convert between amp-hours, watt-hours, and kilowatt-hours given a voltage.
\quad \mathrm{Wh} = \mathrm{Ah}\times V \quad\quad \mathrm{kWh} = \frac{\mathrm{Ah}\times V}{1000} \quad\quad \mathrm{Ah} = \frac{1000\times \mathrm{kWh}}{V}- 1 kWh = 1000 Wh and 1 Wh = 1 V × 1 Ah.
- Metric prefixes: 1000 mAh = 1 Ah and 1000 mV = 1 V.
How do you convert Ah to kWh? Multiply capacity by voltage and divide by 1000: kWh = Ah × V ÷ 1000.
How do you convert kWh to Ah? Multiply energy by 1000 and divide by voltage: Ah = (kWh × 1000) ÷ V.
Ah to kWh Conversion Table
| Capacity (Ah) | Energy (kWh) |
|---|---|
| 1 | 0.012 |
| 2 | 0.024 |
| 5 | 0.060 |
| 10 | 0.120 |
| 12 | 0.144 |
| 20 | 0.240 |
| 25 | 0.300 |
| 30 | 0.360 |
| 40 | 0.480 |
| 50 | 0.600 |
| 60 | 0.720 |
| 75 | 0.900 |
| 80 | 0.960 |
| 90 | 1.080 |
| 100 | 1.200 |
| 120 | 1.440 |
| 150 | 1.800 |
| 200 | 2.400 |
| 250 | 3.000 |
| 300 | 3.600 |
| * Formula: kWh = Ah × V ÷ 1000. Table assumes V = 12. | |
Example Problem
Convert 100 Ah at 12 V to kWh.
Use the formula: kWh = Ah × V ÷ 1000.
kWh = 100 × 12 ÷ 1000 = 1.2 kWh
