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Battery Runtime Calculator

Estimate runtime from voltage, amp-hours and usable capacity.

Tool inputs stay in your browser · optional AI search sends your query

Good to know: Runtime = volts × Ah × usable fraction × efficiency ÷ watts. Load variation, temperature, chemistry and high discharge rates can shorten runtime. Follow manufacturer safety limits.

How to use it (step by step)

  1. 1Fill in the boxes: “Battery voltage”, “Battery capacity (Ah)”, “Load power (W)”, “Usable capacity (%)”, “Conversion efficiency (%)”. Example numbers are already there so you can see how it works; replace them with yours.
  2. 2The result updates instantly as you type (on a phone it is below the boxes).
  3. 3The bold line is the main answer. Tap Copy next to any value to copy it.

Words to know

Time card / hours
Adding up hours worked (minus breaks) to calculate pay. Overtime is time beyond normal hours, often paid at a higher rate.
Percentage
A part out of 100. 25% of 200 = 50.
Fraction / ratio
A fraction is a part of a whole (3/4 = three of four parts). A ratio compares two amounts (2:1 = twice as much).

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