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Volts to Amps Calculator

Convert voltage (volts) to current (amps) using resistance or power.

—Amps
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How to Convert Volts to Amps

There are two primary methods to convert volts (voltage) to amps (current):

Method 1: Using Resistance (Ohm's Law)

Ohm's Law states that current is equal to voltage divided by resistance:

I = V ÷ R or Amps = Volts ÷ Ohms

Example: Calculate the current in a circuit with 120 volts and 10 ohms resistance.
I = 120V ÷ 10Ω = 12A

Method 2: Using Power (Watts)

If you know the power consumption in watts instead of resistance, use:

I = P ÷ V or Amps = Watts ÷ Volts

Example: A 1200-watt appliance running on 120 volts.
I = 1200W ÷ 120V = 10A

Common Voltage-to-Current Conversions

Voltage (V)Resistance (Ω)Current (A)
120V5Ω24A
120V10Ω12A
120V100Ω1.2A
240V10Ω24A
12V (DC)1Ω12A
Voltage (V)Power (W)Current (A)
120V600W5A
120V1200W10A
120V1800W15A
240V2400W10A
12V (DC)60W5A

Typical Current Requirements

Here are some common household and commercial devices and their typical current draws:

  • LED Light Bulb (9W): 0.075A at 120V
  • Laptop Computer: 0.5-1.5A at 120V
  • Refrigerator: 1-2A at 120V (running), 5-8A (startup)
  • Microwave Oven (1000W): 8.3A at 120V
  • Central Air Conditioner: 15-20A at 240V
  • Electric Clothes Dryer: 20-30A at 240V
  • Electric Car Charger (Level 2): 30-40A at 240V

Important Notes on Circuit Safety

  • Circuit breakers and fuses should be sized to handle at least 125% of the continuous load current
  • Wire gauge must be appropriate for the expected current to prevent overheating
  • Always consult an electrician for permanent electrical installations
  • Remember that some devices have higher startup current (inrush current) than their running current

Need to convert in the opposite direction?

Use our Amps to Volts Calculator to convert current to voltage.

Convert Amps to Volts