Watts to Volts Calculator

Q: How do I calculate voltage from watts?

You also need current (amps). DC: Volts = Watts ÷ Amps. AC: Volts = Watts ÷ (Amps × Power Factor).

Q: How many volts is 100 watts at 10 amps?

For DC: 100W ÷ 10A = 10V. This is useful when verifying battery or solar output voltage under load.

Q: When would I need to find voltage from watts?

Common uses: verifying battery terminal voltage under load, checking solar controller output, or confirming transformer secondary voltage given a known load and current.

Find the voltage in a circuit when you know the power (watts) and current (amps). Supports both DC and AC systems.

Calculate Voltage from Watts

Power (Watts)

Current (Amps)

Circuit Type

Power Factor (AC only)

Result

—

Voltage (Volts)

Formulas

DC:

Volts = Watts ÷ Amps

AC:

Volts = Watts ÷ (Amps × Power Factor)

Example Calculations

DC Solar Panel: A 400W panel producing 8.33A.

Volts = 400 ÷ 8.33 = 48V

AC Load: A 2,000W load drawing 9A at PF = 0.95.

Volts = 2000 ÷ (9 × 0.95) = 2000 ÷ 8.55 = 234V

Frequently Asked Questions

How do I calculate voltage from watts?

DC: V = W ÷ A. AC: V = W ÷ (A × PF). You need to know both watts and amps to find voltage. This is the electrical equivalent of solving one unknown in Ohm's law.

How many volts is 100 watts at 10 amps?

DC: 100 ÷ 10 = 10V. This is a useful sanity check — for instance, a 10V battery under load producing 100W through 10A wiring.

When would I need to find voltage from watts?

Common scenarios include: verifying battery terminal voltage under load, checking solar panel operating point, confirming transformer secondary voltage, or diagnosing voltage drop issues in long wire runs.