Watts to Amps Calculator
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Watts to amps formula
The formula for converting watts to amps is:
Amps = Watts ÷ Volts
How to convert watts to amps
To convert watts (electrical power) to amps (electrical current) at a fixed voltage, you can use a variation of Watt's Law formula: Power = Current × Voltage (P = IV). By working backwards, we get the equation: amps = watts ÷ volts, which can be used to convert watts to amps.
Example calculation
If you have an amplfier using 1600W of power on a 120v circuit, you can use the equation Current (Amps) = Power (Watts) ÷ Voltage to calculate that the draw of the amplifier is 1600 / 120 = 13.3 amps.
How many amps is 1000 watts at 240 volts?
If you have a 1000W electrical appliance connected to a 240V circuit, it will be drawing 4.17 amps.
1000W ÷ 240V = 4.17A.
How many amps is 1500 watts at 120 volts?
If you have a 1500W electrical appliance on a 120V circuit, it will be drawing 12.5 amps.
1500W ÷ 120V = 12.5A.
Watts to amps at 120V (AC)
| Watts: | Amps (at 120V): |
|---|---|
| 100 watts | 0.83 amps |
| 200 watts | 1.67 amps |
| 300 watts | 2.5 amps |
| 400 watts | 3.33 amps |
| 500 watts | 4.17 amps |
| 600 watts | 5 amps |
| 700 watts | 5.83 amps |
| 800 watts | 6.67 amps |
| 900 watts | 7.5 amps |
| 1000 watts | 8.33 amps |
| 1100 watts | 9.17 amps |
| 1200 watts | 10 amps |
| 1300 watts | 10.83 amps |
| 1400 watts | 11.67 amps |
| 1500 watts | 12.5 amps |
| 1600 watts | 13.33 amps |
| 1700 watts | 14.17 amps |
| 1800 watts | 15 amps |
| 1900 watts | 15.83 amps |
| 2000 watts | 16.67 amps |
| 2500 watts | 20.83 amps |
| 3000 watts | 25 amps |
Watts to amps at 240V (AC)
| Watts: | Amps (at 240V): |
|---|---|
| 100 watts | 0.42 amps |
| 200 watts | 0.83 amps |
| 300 watts | 1.25 amps |
| 400 watts | 1.67 amps |
| 500 watts | 2.08 amps |
| 600 watts | 2.5 amps |
| 700 watts | 2.92 amps |
| 800 watts | 3.33 amps |
| 900 watts | 3.75 amps |
| 1000 watts | 4.17 amps |
| 1100 watts | 4.58 amps |
| 1200 watts | 5 amps |
| 1300 watts | 5.42 amps |
| 1400 watts | 5.83 amps |
| 1500 watts | 6.25 amps |
| 1600 watts | 6.67 amps |
| 1700 watts | 7.08 amps |
| 1800 watts | 7.5 amps |
| 1900 watts | 7.92 amps |
| 2000 watts | 8.33 amps |
| 2500 watts | 10.42 amps |
| 3000 watts | 12.5 amps |
Understanding watts, amps and volts
To help understand the conversion of watts to amps, let's go through what each of these units represent.
What are amps?
Amps are amperes, a unit which measures electrical current. It can be helpful to imagine electrical current as water in a hose. In this analogy, the quantity (volume) of water would be the amps.
What are watts?
Watts represent the amount of energy produced by the amps and volts working together. Multiplying amps (water volume) by volts (water pressure) gives you the wattage (the resulting power or energy). A water wheel would turn faster and longer, generating more energy if it uses increased water volume and higher water pressure; the same applies to the wattage if amps and volts are increased.
What are volts?
Volts are a unit to measure force. They measure the force required to make the electrical current (amps) flow. In the hose analogy, the volts would be the water pressure. North American homes typically use 120V for their electrical supply, whilst 230V is common across many other countries.
What is AC/DC?
DC stands for direct current, when the current flows in one single direction. A flashlight with a battery uses a direct current.
AC stands for alternating current, when the current periodically changes direction. In Northern America and Western Japan, this usually happens 60 times per second, or 60Hz / hertz. In Europe, the UK, East Japan and most of Australia, South America, Africa and Asia, the current changes direction 50 times per second, which is 50Hz. Power supplied to homes and businesses uses AC supply.
Watts to amps conversion examples
Let's go through some examples to help nail the conversion process.
Example question 1
Question: 600W are being sent at 120V. What is the current?
- Current = Power ÷ Voltage
- Current = 600W ÷ 120V
- Current = 5A
If you’re working with larger units, you need to remember that 1 kilowatt is equal to 1000 watts. The formula for Watt’s law stays the same, just as long as you express the wattage in watts (your sum will go wrong if you use ‘5W’ to mean ‘5KW’; you need to use 5000W instead).
Example question 2
Question: 2.4KW are being sent at 120V. What is the current?
Before we carry out our conversion, we need to convert 2.4 kilowatts into watts. 2.4KW = 2400W. We can then run through the formula...
- Current = Power ÷ Voltage
- Current = 2400W ÷ 120V
- Current = 20A
Converting watts to amps is simple, really, but if you’re feeling short-circuited after all those numbers, just use our watts to amps calculator at the top of this page.
Calculator by Alastair Hazell Last updated: November 4, 2022This page has been reviewed by Derek Bulled, Director of CDS Electrical and an approved electrician with over 30 years of experience.
References
- What is Watt’s law?, EngineeringClicks.
- How Much Electrical Power Do You Need?, Mississippi State University.
- Unit 4: Energy Through Our Lives-Part II, University of Wisconsin - Stevens Point.
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