Watt's law suite

Watts to Amps Calculator

A = W ÷ V

Watts to Amps Calculator

Convert Watts back into Amperes.

Live Result
Formula-backed — instant professional result
System Type
CALCULATED CURRENT
0 A
Also equals 0 mA
Formula used A = W ÷ V The primary result is shown in A using the formula displayed above. 1200W ÷ 120V = 10A

This calculator is an educational planning estimate. Verify safety-critical work with equipment nameplate data, local electrical code, and a qualified professional.

Voltage Amps Watts Calculator for volts, amps, watts, ohms, power factor, AC, DC, 12V, 240V, 3 phase, kW, kVA, kWh, wire ampacity, generator, inverter, battery, solar, and amplifier calculations.

DC amps to watts

Direct-current circuit loop

Voltage Amps Watts Calculator for volts, amps, watts, ohms, power factor, AC, DC, 12V, 240V, 3 phase, kW, kVA, kWh, wire ampacity, generator, inverter, battery, solar, and amplifier calculations.

120V DC formula-first page-specific visual

Watts to Amps Calculator — Convert Watts to Amps | Ampstowatt Guide

DC circuit loop

Battery voltage and current converted directly into watts

DC pages need a clean loop: battery, load, current direction, and watts without power factor.

Formula P = V x I
Watts to Amps Calculator — Convert Watts to Amps | Ampstowatt technical circuit diagram A premium electrical diagram showing the main values and conversion flow for Watts to Amps Calculator — Convert Watts to Amps | Ampstowatt. 120 V battery 10 A 1200 W Fuse Load Load
Watts to Amps Calculator — Convert Watts to Amps | Ampstowatt DC circuit loop with real formula values and planning checkpoints.

Quick answer

Use this calculator when DC current and voltage convert directly into watts.

DC systems do not use power factor, so the calculation is direct. This is useful for batteries, automotive systems, LED drivers, electronics, and solar DC accessories.

P = V x I

Inputs to check before calculating

  • Use measured voltage when battery voltage is above or below nominal.
  • Enter continuous current for heat and runtime planning.
  • Check fuse and wire ratings against the calculated current.
  • For battery loads, convert watts into Wh for runtime estimates.

Example: 10 amps at 120 volts

At 120 volts, 10 amps equals 1,200 watts before AC power-factor adjustments. Formula: 10 A x 120 V = 1,200 W.

Best use cases

  • Find watts from V and A
  • Clear formula context
  • General electrical planning
  • DC load planning with clear unit labels.

Common mistake to avoid

Do not assume a 12V battery is always exactly 12.0V; charging and resting voltage can change the watt result.

How to use the result

Use the watt output to compare loads, size power supplies, and estimate battery energy use.

Accuracy and safety note

Calculator output is a planning estimate. Final breaker sizing, wire gauge, derating, voltage-drop limits, equipment protection, and code compliance should be verified with manufacturer documentation and a qualified electrician or engineer.

For the broad formula, reference table, and breaker planning context, start with the main Amps to Watts Calculator.

Related Electrical Conversions

Start with the main conversion tool

Continue through the reverse and related conversion tools that support amps, watts, kW, VA, kVA, and battery energy planning.Amps to Watts Calculator

Methodology, Review Notes, and Sources

How this calculator works

The calculator applies Watt's law for DC and resistive loads, then adds power factor for AC loads and the 1.732 multiplier for balanced three-phase line-to-line calculations.

  • DC and resistive loads: W = A x V
  • Single-phase AC: W = A x V x PF
  • Three-phase AC: W = 1.732 x A x V x PF

Editorial review

Last reviewed: June 26, 2026. Ampstowatt.com is built around the amps to watts conversion — our core specialty. Content is maintained by the Ampstowatt editorial team and checked for formula consistency, unit labels, calculator behavior, and safety wording.

The page is an educational planning reference, not a licensed electrical design or inspection service.

Reference sources

FAQ

Watts to Amps FAQ

Fast answers before you use the calculator or compare formulas.

W How do I convert 120V amps to watts?

Multiply the current in amps by 120 volts. For example, 5 amps at 120V equals 600 watts (5 × 120 = 600). DC conversions do not require a power factor because current and voltage are always in phase.

BAT How many watts can a 120V battery deliver?

A 120V battery's power output depends on current draw. At 10A, it delivers 1200W. At 20A, it delivers 2400W. The maximum safe current depends on the battery's internal resistance, terminal rating, and fuse protection. Always check the battery data sheet for maximum discharge rate.

DC Why is DC conversion simpler than AC?

DC circuits have no power factor because current and voltage don't alternate. The formula is simply Watts = Amps × Volts. AC circuits have reactive power from inductors and capacitors that requires a power factor correction, making the formula Watts = Amps × Volts × PF.

AWG What wire gauge do I need for 120V DC?

Wire gauge for 120V DC depends on current, distance, and acceptable voltage drop. Low-voltage DC circuits are especially sensitive to voltage drop because a 0.5V loss is a larger percentage of 120V than of 120V. Use the wire gauge calculator with one-way distance and 120V to find the right conductor size.

PV Can I use this calculator for solar panel circuits?

Yes, but use the correct voltage point. Solar panels operate at Vmp (maximum power voltage), not the battery voltage. A 12V-nominal panel may have Vmp of 17–18V. For battery-side current, use the battery voltage. For panel-side wiring, use the panel Vmp.

RUN How do I calculate battery runtime from watts at 120V?

First convert amps to watts (A × 120V). Then convert battery capacity: Watt-hours = Amp-hours × 120V. Divide Wh by the load watts to estimate runtime in hours. Account for inverter efficiency (typically 85–92%) if converting DC to AC. Use the amp-hours to watt-hours calculator for detailed estimates.