Amperage Load Calculator

Estimate amperage load from watts, voltage, phase type, power factor, and multiple electrical loads. This calculator also estimates adjusted continuous load, breaker size, fuse size, remaining capacity, and load percentage.

Calculate Amperage Load

Single-phase amps = watts ÷ (volts × power factor). Three-phase amps = watts ÷ (√3 × volts × power factor).
Your result will appear here.

How the amperage load calculator works

Load amps:
The calculator converts watts or volt-amps into current based on voltage, phase type, and power factor.

Adjusted amps:
Continuous load and optional safety factors are applied to estimate planning amperage.

Circuit comparison:
The result is compared to the selected circuit rating to estimate load percentage and remaining amps.

Why use an amperage load calculator?

An amperage load calculator helps estimate how many amps a device, circuit, appliance, or group of loads may draw.

It can help with breaker planning, fuse planning, wire sizing, circuit load checks, appliance loads, lighting loads, EV chargers, heaters, motors, DC circuits, and general electrical planning.

What your result means

Your result shows load amps, adjusted amps, total watts, volt-amps, recommended breaker size, recommended fuse size, estimated wire size, circuit load percentage, remaining amps, and multiple load row totals.

Amperage load calculator formulas

Frequently asked questions

How do I calculate amperage load?

For a basic single-phase load, divide watts by volts. If power factor is used, divide watts by volts times power factor.

How many amps is 2,400 watts at 120 volts?

At 120 volts and a power factor of 1.0, 2,400 watts is 20 amps.

What does adjusted amperage mean?

Adjusted amperage includes planning factors such as continuous load or extra safety margin. It is useful when comparing a load to a breaker, fuse, or wire size.

Can this replace electrical code calculations?

No. This is a simplified planning calculator. Final circuit sizing depends on conductor size, insulation rating, breaker or fuse size, equipment nameplate ratings, derating, and local electrical code.