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Estimate Current Draw from a Battery

Find the current a load pulls so you can estimate battery runtime.

No cal iniciar sessió
V
A
Ω
W
Enter any two values and the other two are solved automatically

💡 Ohm's law: V = I × R. Power adds P = V × I. Knowing any two lets you derive the rest — handy for sizing resistors, checking LED current, or working out heat dissipation.

Battery tips

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Enter battery voltage and the load resistance (or power) to get current draw in amps.

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Runtime ≈ battery capacity (Ah) ÷ current draw (A) — lower current means longer life.

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Real batteries sag under load and aren't 100% efficient, so treat the runtime as an optimistic estimate.

Com funciona

1
Introdueix
Enter your data into the tool above. Everything stays local to your browser.
2
Processa
The tool processes your data instantly in your browser using JavaScript. No server, no waiting.
3
Descarrega
Get your result instantly. Nothing is stored after you leave the page — complete privacy.

Per què usar la nostra?

✓Completament gratuït — sense costos ocults, mai
✓No cal compte, correu electrònic ni inici de sessió
✓Els fitxers no surten mai del teu dispositiu
✓Sense cap límit de mida de fitxer
✓Sense marques d'aigua en cap sortida

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