Battery runtime
Estimate ideal runtime from battery energy, usable capacity, efficiency and load. Change the inputs to update the chart or diagram.
Your inputs
The editable example is illustrative. Enter your own dimensions, operating data, prices, and fees. Results update as you edit.
Calculations run in your browser. Inputs are not saved or sent to analytics.
How it works
- Usable delivered energy = × × ; Estimated runtime = Usable delivered energy (Wh) ÷ (W); = ×
- Worked example: 500 Wh × 0.8 × 0.9 = 360 Wh; 360 Wh /100 W = 3.6 h
- Supported input limits: : 0 ≤ x ≤ 1,000,000,000,000; : 1e-12 ≤ x ≤ 1,000,000,000,000; : 0 ≤ x ≤ 1,000,000,000,000; : 0 ≤ x ≤ 1; : 0 ≤ x ≤ 1; : 1e-12 ≤ x ≤ 1,000,000,000,000
Input and formula key
Your result
Complete the inputs to see your result.
Assumptions and limitations
Ah requires the battery’s voltage to estimate Wh. Usable fraction and efficiency separately reduce delivered energy before division by a constant load. Aging, temperature, discharge-rate effects and inverter standby consumption are not automatically modeled.
Sources
- EIA — watts and watt-hours Sources reviewed: 2026-10-06
