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Single conversion
To convert from Joule (J) to Watt-hour (Wh), use the following formula:
Let's convert 5 Joule (J) to Watt-hour (Wh).
Using the formula:
Therefore, 5 Joule (J) is equal to Watt-hour (Wh).
Here are some quick reference conversions from Joule (J) to Watt-hour (Wh):
| Joules | Watt-hours |
|---|---|
| 0.000001 J | Wh |
| 0.001 J | Wh |
| 0.1 J | Wh |
| 1 J | Wh |
| 2 J | Wh |
| 3 J | Wh |
| 4 J | Wh |
| 5 J | Wh |
| 6 J | Wh |
| 7 J | Wh |
| 8 J | Wh |
| 9 J | Wh |
| 10 J | Wh |
| 20 J | Wh |
| 30 J | Wh |
| 40 J | Wh |
| 50 J | Wh |
| 100 J | Wh |
| 1000 J | Wh |
| 10000 J | Wh |
For all Energy converters, choose units using the From/To dropdowns above.
The joule (J), as part of the International System of Units (SI), is a fundamental unit used to measure energy.
Whether you're discussing the electricity that powers your home, the work done by a machine, or the energy you get from food, the joule is the universal standard.
Key Takeaways:
A joule (J) represents the amount of work done when a force of one newton moves an object by one meter.
This is formally expressed as:
1 J = 1 N·m
To make that simpler, think of it this way: lifting a small apple (which weighs about one newton) one meter straight up requires about one joule of energy.
This direct link between force, distance, and energy makes the joule a cornerstone unit in physics and engineering.
It's easy to mix up joules and watts, but the key difference is time.
Specifically, one watt is equal to one joule of energy transferred per second (1 W = 1 J/s).
For example, a 100-watt light bulb uses 100 joules of electrical energy every second it is on.
While many food labels use calories (specifically kilocalories, or kcal), the official SI unit for food energy is the joule.
The conversion is straightforward:
1 food calorie (kcal) ≈ 4,184 joules or 4.184 kilojoules (kJ)
Using joules and kilojoules (kJ) provides a universal, scientific standard for measuring the energy we get from food. This is why you will often see "kJ" on nutrition labels in many parts of the world.
Ever looked at the back of a battery pack and felt confused by the numbers? You're not alone!
One of the most important measurements you'll see is the Watt-hour (Wh).
Think of it as the fuel gauge for your electronic devices. This simple guide will break down precisely what a Wh is and why it matters.
A Watt-hour (Wh) is a unit that measures energy. Specifically, it tells you how much energy a device uses over a specific period.
The concept is simple: one Watt-hour is the amount of energy consumed when one watt of power is used for precisely one hour.
A helpful analogy is a car's gas tank. The Watt-hour rating on a battery is like the size of the tank—it tells you the total amount of energy it can store.
The power your device draws (measured in Watts) is like how fast you're driving and using up that gas.
A battery with a higher Wh rating holds more energy and can power your device for longer, just like a larger gas tank lets you drive farther.
You'll find Wh ratings on many of the rechargeable devices you use daily. It's a key indicator of battery capacity and runtime. Some common examples include:
The Watt-hour is directly related to the joule (J), which is the standard scientific unit for energy. The conversion is straightforward:
This is because a watt is defined as one joule per second, and there are 3,600 seconds in an hour (60 seconds × 60 minutes).
A kilowatt-hour (kWh) is simply 1,000 Watt-hours. The prefix "kilo-" means one thousand.
You're probably most familiar with kWh from your home electricity bill. Utility companies use this larger unit to measure your household's monthly energy consumption.
So, when you see that you used 500 kWh last month, it means you used 500,000 Watt-hours of energy.