Watts to Amps Calculator

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Use this calculator to convert watts to amps and amps to watts. Options are available for both alternating current (AC) and direct current (DC). Conversion charts, are available further down the page.


Disclaimer: Whilst every effort has been made in building this calculator, we are not to be held liable for any damages or monetary losses arising out of or in connection with the use of it. This tool is here purely as a service to you, please use it at your own risk. Full disclaimer. Do not use calculations for anything where loss of life, money, property, etc could result from inaccurate calculations.

How do you convert watts to amps?

The formula for converting watts to amps (at a fixed voltage) is:

amps = watts ÷ volts
  • 1500 watts / 120 volts = 12.5 amps
  • 3000 watts / 120 volts = 25 amps

How do you convert amps to watts?

The formula for converting amps to watts (at a fixed voltage) is:

watts = amps × volts
  • 15 amps × 120 volts = 1800 watts
  • 20 amps × 120 volts = 2400 watts
Watts and amps conversions at 120V (AC)
Power Current Voltage
50 watts 0.417 amps 120 volts
100 watts 0.833 amps 120 volts
150 watts 1.25 amps 120 volts
200 watts 1.667 amps 120 volts
250 watts 2.083 amps 120 volts
300 watts 2.5 amps 120 volts
350 watts 2.917 amps 120 volts
400 watts 3.333 amps 120 volts
450 watts 3.75 amps 120 volts
500 watts 4.167 amps 120 volts
600 watts 5 amps 120 volts
700 watts 5.833 amps 120 volts
800 watts 6.667 amps 120 volts
900 watts 7.5 amps 120 volts
1000 watts 8.333 amps 120 volts
1100 watts 9.167 amps 120 volts
1200 watts 10 amps 120 volts
1300 watts 10.833 amps 120 volts
1400 watts 11.667 amps 120 volts
1500 watts 12.5 amps 120 volts
1600 watts 13.333 amps 120 volts
1700 watts 14.167 amps 120 volts
1800 watts 15 amps 120 volts
1900 watts 15.833 amps 120 volts
2000 watts 16.667 amps 120 volts
2100 watts 17.5 amps 120 volts
2200 watts 18.333 amps 120 volts
2300 watts 19.167 amps 120 volts
2400 watts 20 amps 120 volts
2500 watts 20.833 amps 120 volts
Note: conversions are for guide-purposes only and are rounded to maximum 3 decimal places.
Watts and amps conversions at 12V (DC)
Power Current Voltage
5 watts 0.417 amps 12 volts
10 watts 0.833 amps 12 volts
15 watts 1.25 amps 12 volts
20 watts 1.667 amps 12 volts
25 watts 2.083 amps 12 volts
30 watts 2.5 amps 12 volts
35 watts 2.917 amps 12 volts
40 watts 3.333 amps 12 volts
45 watts 3.75 amps 12 volts
50 watts 4.167 amps 12 volts
60 watts 5 amps 12 volts
70 watts 5.833 amps 12 volts
80 watts 6.667 amps 12 volts
90 watts 7.5 amps 12 volts
100 watts 8.333 amps 12 volts
110 watts 9.167 amps 12 volts
120 watts 10 amps 12 volts
130 watts 10.833 amps 12 volts
140 watts 11.667 amps 12 volts
150 watts 12.5 amps 12 volts
160 watts 13.333 amps 12 volts
170 watts 14.167 amps 12 volts
180 watts 15 amps 12 volts
190 watts 15.833 amps 12 volts
200 watts 16.667 amps 12 volts
210 watts 17.5 amps 12 volts
220 watts 18.333 amps 12 volts
230 watts 19.167 amps 12 volts
240 watts 20 amps 12 volts
250 watts 20.833 amps 12 volts
Note: conversions are for guide-purposes only and are rounded to maximum 3 decimal places.

Understanding watts, amps and volts

If trying to convert amps, watts and volts manually has got you feeling wired, then settle down and plug in to our handy guide to discover what’s watt. You’re sure to have a lightbulb moment in no time!

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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.

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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.

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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.

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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.

How to convert amps to watts manually

The Watt’s Law formula is all that’s needed for these unit conversions. The wattage (power produced / P) is calculated by multiplying the amps (current / I) by the voltage (force / E):

Power (P) = Current (I) x Voltage (E)

So…

watts = amps × volts

Example: 5 amps are being sent at 120 volts. What’s the wattage?

Power = Current x Voltage
Power = 5A x 120V
Power = 600W

How to convert watts to amps

To find the amps, you work backwards with Watt’s Law and divide the wattage by the volts:

Current (I) = Power (P) ÷ Voltage (E)

So…

amps = watts ÷ volts

Example: 600 watts are being sent at 120 volts. What's the current?

Current = Power ÷ Voltage
Current = 600W ÷ 120V Current = 5A

And…

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: 2.4KW watts are being sent at 120 volts

Current = Power ÷ Voltage
Current = 2400W ÷ 120V
Current = 20A

It’s simple, really, but if you’re feeling short-circuited after all those numbers, just use our watts and amps conversion calculator above.

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