Amps Calculator
Calculate amps from watts and volts using I = P / V, or from volts and resistance using I = V / R.
Current— A
How to Calculate Amps
I = P / V
Current (amps) equals power (watts) divided by voltage (volts). This formula is essential for determining the current draw of any electrical device.
Alternative Formula (Ohm's Law)
I = V / R
Current also equals voltage divided by resistance (ohms). Use this when you know the circuit resistance instead of power.
Example:
A 1,200W microwave on a 120V circuit:
I = 1200 / 120 = 10 amps
A 1,200W microwave on a 120V circuit:
I = 1200 / 120 = 10 amps
FAQ
What is an amp?
An ampere (amp) is the SI unit of electric current. It measures the rate of electron flow through a conductor.
How many amps can a standard outlet handle?
In the US, most household circuits are rated for 15A or 20A. A standard outlet on a 15A circuit should not exceed 12A continuous load (80% rule).
Last updated: 2026-08-08