Ampere Hour to Watt Hour Calculator
Convert amp-hours (Ah) to watt-hours (Wh) with voltage—instant bidirectional Wh ↔ Ah (also mAh / kWh). Not a runtime or UPS Ah sizing tool.
Calculator
Quick: Ah + V → Wh. Advanced: Wh → Ah, mAh, or kWh units.
About this calculator
This ampere hour to watt hour calculator converts charge (Ah) to energy (Wh) with Wh = Ah × V. It does not estimate runtime hours or UPS backup minutes. For DC pack hours use battery runtime; for UPS Ah procurement use UPS battery sizing. Browse the power calculator hub.
Calculation Results
≈ 1200 Wh (1.200 kWh)
100 Ah × 12 V
Formula: Wh = Ah × V
Uses nominal voltage. Real usable Wh depends on DoD, temperature, and discharge rate—screen only.
Ah to Wh quick reference (common voltages)
Wh = Ah × V · kWh = Wh ÷ 1000 · Ah = mAh ÷ 1000. Click a row to load the calculator.
| Capacity | Voltage | Energy |
|---|---|---|
| 12 V | 1200 Wh (1.2 kWh) | |
| 24 V | 2400 Wh (2.4 kWh) | |
| 48 V | 4800 Wh (4.8 kWh) | |
| 3.7 V | 7.4 Wh | |
| 12 V | 100 Ah | |
| 12 V | ≈ 16.7 Ah |
mAh ↔ Ah and Ah ↔ kWh
- Ah = mAh ÷ 1000 (2000 mAh = 2 Ah). mAh = Ah × 1000.
- kWh = (Ah × V) ÷ 1000. Example: 100 Ah × 12 V = 1.2 kWh.
- Ah = (kWh × 1000) ÷ V. Use Wh→Ah mode with the kWh unit selected.
Ampere hour to watt hour formula
Wh = Ah × V
Reverse: Ah = Wh ÷ V · kWh = Wh ÷ 1000 · Ah = mAh ÷ 1000.
- Ah — amp-hours (charge capacity).
- V — nominal battery voltage (volts).
- Wh — watt-hours (energy).
Example: 100 Ah × 12 V = 1200 Wh (1.2 kWh).
Need hours at a load? Battery runtime calculator. UPS string Ah: UPS battery calculator.
When to use which battery tool
| Goal | Tool |
|---|---|
| Convert Ah ↔ Wh (unit conversion) | This page — Ah to Wh |
| DC pack hours from Ah / V / load | Battery runtime calculator |
| UPS Ah for target backup minutes | UPS battery sizing |
| Series/parallel string layout | UPS battery bank |
Frequently Asked Questions
How do I convert ampere hours to watt hours?
Wh = Ah × V. Example: 100 Ah at 12 V = 1200 Wh (1.2 kWh). Voltage is required because amp-hours measure charge, not energy.
How do I convert watt hours to ampere hours?
Ah = Wh ÷ V. Example: 1200 Wh at 12 V = 100 Ah. Switch to Wh → Ah mode above.
How do I convert mAh to Ah or Ah to kWh?
Ah = mAh ÷ 1000 (2000 mAh = 2 Ah). kWh = (Ah × V) ÷ 1000—select mAh or kWh units above. Example: 100 Ah × 12 V = 1.2 kWh.
What is the amp hour formula?
Amp-hours measure charge: Ah = A × hours. Energy needs voltage: Wh = Ah × V. Average current from capacity and time: A = Ah ÷ hours on the Ah to amps calculator.
What is 100Ah in watts?
Ah alone is not watts. Energy is Wh = Ah × V (100 Ah × 12 V = 1200 Wh). Continuous power in watts depends on discharge rate; at roughly a 1C rate for one hour, power ≈ Ah × V (~1200 W at 12 V).
How many amp hours is 200W?
Watts are power. Capacity needs time: Ah ≈ (W × hours) ÷ V. Example: 200 W for 5 h at 12 V ≈ 83.3 Ah before DoD and losses—or use the battery runtime reverse-Ah mode.
Is Ah to Wh the same as a battery runtime calculator?
No. This page only converts energy units. For hours at a load use battery runtime. For Ah ÷ hours → amps use Ah to amps. For UPS minutes use UPS runtime.