Amps to Volts Calculator
Convert current in amps (A) to voltage in volts (V). Select the calculation type — amps to volts with watts or amps to volts with ohms — enter the amps plus watts or ohms, and press Calculate to get volts. Everything runs locally in your browser.
Choose the calculation type
Pick "amps to volts with watts" when you know the power in watts, or "amps to volts with ohms" when you know the resistance in ohms. The second input switches to match.
Enter amps and watts or ohms
Type the current in amps, then the power in watts (watts mode) or the resistance in ohms (ohms mode). Both values must be zero or higher; watts mode also requires a current above zero.
Press Calculate, read volts
The result appears in volts (V), rounded to at most three decimals. Copy the result to your clipboard, or press Reset to clear everything and start over.
How amps become volts
- How do you convert amps to volts with watts?
- The voltage V in volts (V) is equal to the power P in watts (W), divided by the current I in amps (A): V(V) = P(W) / I(A). For example, 1200 W drawn at 10 A gives 1200 / 10 = 120 V.
- How do you convert amps to volts with ohms (Ohm's law)?
- The voltage V in volts (V) is equal to the current I in amps (A), times the resistance R in ohms (Ω): V(V) = I(A) × R(Ω). For example, 3 A through a 10 Ω resistor gives 3 × 10 = 30 V.
- Why does watts mode reject zero amps?
- V = P / I divides by the current, and division by zero is undefined — with zero current a power figure alone cannot tell you the voltage. In ohms mode, however, 0 A is valid: 0 A × R Ω simply yields 0 V.
- Which formula should I use?
- Use the watts formula when you know how much power the load consumes, and the ohms formula when you know the load's resistance. They are consistent: combining P = V × I with V = I × R gives P = I² × R.
- Worked example
- A device carries 0.5 A and consumes 100 W: V = 100 W / 0.5 A = 200 V. The same current through 400 Ω checks out with Ohm's law: 0.5 A × 400 Ω = 200 V.
Privacy: every calculation runs in your browser tab — no value you type is sent anywhere. Copy result uses your clipboard only. Values are ideal DC / single-phase resistive results; verify real installations with a multimeter.