Use our interactive calculator to easily convert watt hours to watts (Wh to W):
Watt Hours to Watts Conversion Calculator
watts (W)
Conversion formula: watts = watt hours ÷ hours
Or would you instead like to convert watts to watt hours?
How to Convert Watt Hours to Watts (Wh to W)
To convert watt hours to watts, divide watt hours by hours.
Formula: watts = watt hours ÷ hours
Abbreviated: W = Wh ÷ hrs
Example
Let's say you have an appliance that runs for 2 hours and consumes 100 watt hours. Here's how to calculate how many watts it uses:
100 Wh ÷ 2 hrs = 50 W
So, in this example, your appliance uses an average of 50 watts when running.
Why Convert Watt Hours to Watts?
Devices that track electricity usage -- such as electricity usage monitors and watt meters -- often report usage in watt hours (Wh) or kilowatt hours (kWh).
These units are great for knowing how much energy a device or appliance uses over time. And knowing that can help you when doing things like buying batteries and reducing your energy usage.
But, at other times, it pays to know how many watts a device uses. That can help when sizing things like inverters, which are rated in watts.
It's important to note that converting watt hours to watts gives you the average energy usage during that time period. Most devices and appliances consume different amounts of energy at different points in time. A fridge cycles through periods of cooling, for instance, during which it uses much more energy.
So, although converting watt hours to watts can be useful, it is also limited. It may not give you all the information you need, such as the maximum wattage that a device uses. For that information, you may need to turn to the product label or manual, or use an electricity usage monitor.
Watts vs Watt Hours: What’s the Difference?
Watts tell you how much power something is using at a given moment, while watt hours tell you how much total energy something consumed over a period of time.
For example, if you leave a 10 watt LED lightbulb on for 3 hours, it will always be consuming 10 watts of power. But, at the end of the 3 hours, it will have used 30 watt hours of energy.
10 W × 3 hrs = 30 Wh
Watts are useful when sizing electrical equipment such as inverters, which are rated based on how many watts they can handle at a given moment.
Watt hours are useful when sizing batteries, because calculating how many watt hours a device or appliance uses gives you a sense of how big of a battery you need to buy to power it.
How to Convert Watts to Watt Hours (W to Wh)
Need to convert the other way?
To convert watts to watt hours, multiply watts times hours.
Formula: watt hours = watts × hours
Abbreviated: Wh = W × hrs
Example
Let’s say you have a fan that consumes 100 watts when on. It runs for 4 hours per day. To calculate its daily energy usage in watt hours, you multiply 100 watts times 4 hours:
100 W × 4 hrs = 400 Wh
In this scenario, your fan consumes 400 watt hours per day.
How to Convert Kilowatt Hours to Watts (kWh to W)
Kilowatt hours are the units you’ll see on your electricity bill. 1 kilowatt hour is equal to 1000 watt hours, like how 1 kilogram is equal to 1000 grams.
To convert kilowatt hours to watts, multiply kilowatt hours times 1000 then divide by hours.
Formula: watts = kilowatt hours × 1000 ÷ hours
Abbreviated: W = kWh × 1000 ÷ hrs
Calculator: Kilowatt Hours to Watts Calculator
Example
Let's say your power bill says you consumed 18 kWh on a particular day. To figure out how much electricity your house was using that day, you do the following:
18 kWh × 1000 ÷ 24 hrs = 750 W
On that day, your house was using an average of 750 watts.
Note: Of course, how much electricity your house is using at any given moment can vary greatly. When running energy-intensive appliances such as dryers and microwaves, for instance, it can be consuming thousands of watts. Alternatively, at night when most of the lights and appliances are off, it may be consuming only a few hundred watts.
How to Convert Watt Hours to Amp Hours (Wh to Ah)
Watt hours tell you how much energy an appliance uses. They can also tell you how much energy a battery stores. And, when it comes to batteries, you can also convey the amount of energy they store in terms of amp hours (Ah).
To convert watt hours to amp hours, divide watt hours by volts.
Formula: amp hours = watt hours ÷ volts
Abbreviated: Ah = Wh ÷ V
Calculator: Convert Watt Hours to Amp Hours
Example
You have a 1500 watt hour solar generator. You look in the product manual and see that the battery voltage is 25 V. Here’s how to calculate its capacity in amp hours:
1500 Wh ÷ 25 V = 60 Ah
Your solar generator has a battery capacity of 60 amp hours.
How to Convert Watt Hours to Volts (Wh to V)
If you instead want to convert watt hours to volts, just divide watt hours by amp hours.
Formula: volts = watt hours ÷ amp hours
Abbreviated: V = Wh ÷ Ah
Example
Let's say you have a 1200 watt hour lithium battery. You know it has a capacity of 100 amp hours. Here's how to calculate its voltage:
1200 Wh ÷ 100 Ah = 12 V
So, in this example, your lithium battery is a 12 volt battery.
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