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Estimate Current Draw from a Battery

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

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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.

Cum funcționează

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

De ce să folosești al nostru?

✓Complet gratuit — fără costuri ascunse, niciodată
✓Fără cont, email sau autentificare necesară
✓Fișierele nu părăsesc niciodată dispozitivul tău
✓Fără limite de dimensiune a fișierelor
✓Fără filigrane pe niciun rezultat

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Întrebări frecvente

Back to Ohm's Law Calculator