Calculating your runtime is straightforward once you know the Inverter Runtime formula and what each input means. This guide explains the method in plain language, walks through a manual calculation, and gives worked examples you can follow — then you can do it instantly with the Inverter Runtime Calculator.
What is Inverter Runtime?
The Inverter Runtime calculation tells you your runtime from a few simple inputs. The figure you are solving for here is the runtime.
The Inverter Runtime formula
The core formula is:
Runtime = Battery energy × Inverter efficiency ÷ 100 ÷ LoadHere is what each input means:
- Battery energy — a value measured in Wh. Example: 1,200 Wh.
- Inverter efficiency — a percentage, such as an annual rate. Example: 85%.
- Load — a value measured in W. Example: 200 W.
How to calculate it step by step
- Write down the battery energy (for example, 1,200 Wh).
- Write down the inverter efficiency (for example, 85%).
- Write down the load (for example, 200 W).
- Apply the formula above to get your runtime.
- Double-check the result with the Inverter Runtime Calculator.
Worked examples
Example 1
| Input / Output | Value |
|---|---|
| Battery energy | 1,200 Wh |
| Inverter efficiency | 85% |
| Load | 200 W |
| Runtime | 5.10 |
| In minutes | 306 |
With battery energy of 1,200 Wh, inverter efficiency of 85% and load of 200 W, the runtime works out to 5.10.
Example 2
With battery energy of 2,400 Wh, inverter efficiency of 85% and load of 200 W, the runtime works out to 10.20.
| Result | Value |
|---|---|
| Runtime | 10.20 |
| In minutes | 612 |
Example 3
With battery energy of 600 Wh, inverter efficiency of 85% and load of 200 W, the runtime works out to 2.55.
| Result | Value |
|---|---|
| Runtime | 2.55 |
| In minutes | 153 |
Tips for an accurate result
- Keep your units consistent — mixing, say, months with years or grams with kilograms is the most common source of error.
- Round only at the very end. Rounding inputs early can shift the final answer noticeably.
- Re-run the numbers whenever an input changes, rather than estimating from an old result.
Prefer not to do the maths by hand? — the Inverter Runtime Calculator does it instantly, for free, with the formula and a worked example built in.
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