Convert Watt-hours to Joules
Convert Watt-hours to Joules instantly. 1 Watt-hour (Wh) equals 3,600 Joules (J).
Watt-hours to Joules conversion table
| Watt-hours (Wh) | Joules (J) |
|---|---|
| 1 Wh | 3,600 J |
| 2 Wh | 7,200 J |
| 3 Wh | 10,800 J |
| 5 Wh | 18,000 J |
| 10 Wh | 36,000 J |
| 20 Wh | 72,000 J |
| 50 Wh | 180,000 J |
| 100 Wh | 360,000 J |
| 500 Wh | 1,800,000 J |
| 1,000 Wh | 3,600,000 J |
1 Watt-hour = 3,600 Joules · multiply Watt-hours by 3,600
About converting Watt-hours to Joules
Watt-hours (Wh) and Joules (J) are both units of energy, so converting between them is a single multiplication: multiply your Watt-hours figure by 3,600. Ten Watt-hours comes to 36,000 Joules, and a hundred works out at 360,000 Joules.
Rule of thumb: going from Watt-hours to Joules multiplies, so the figure always grows — one Watt-hour is already 3,600 Joules. If your answer came out smaller, you have the conversion the wrong way round.
What is a Watt-hour?
A watt-hour is energy, not power, and that distinction trips people up constantly. A watt is a rate — energy per second — so a watt-hour is what you get by sustaining that rate for an hour: a quantity of energy expressed as "this much power for this long". It is the natural unit for anything that stores energy and releases it gradually, which is why phone and laptop batteries are rated in watt-hours rather than the milliamp-hours stamped on the cell, and why airlines police lithium batteries by their watt-hour rating. Capacity in watt-hours tells you how long a load can run; watts alone never can.
What is a Joule?
The joule is the SI unit of energy and the reference every other energy unit here is defined against. One joule is one newton acting over one metre — push with a newton of force, move a metre, and you have spent a joule. It is named after James Prescott Joule, whose painstaking experiments established that heat and mechanical work are the same thing, measurable in the same units. That result sounds obvious now and was foundational then: it collapsed heat, motion and work into a single quantity called energy, which is why one unit can serve food, electricity, explosives and engines alike.
To put both in perspective: a phone battery holds somewhere around 15 watt-hours, while lifting an apple one metre takes about a joule.
The converter above updates as you type, and the table lists common values for quick reference. Need the opposite direction? Use the Joules to Watt-hours converter, or browse all Energy converters.
Frequently asked questions
How many Joules are in one Watt-hour?
There are 3,600 Joules in one Watt-hour.
How do I convert Watt-hours to Joules?
Multiply the number of Watt-hours by 3,600. For example, 10 Watt-hours = 36,000 Joules.
What is 100 Watt-hours in Joules?
100 Watt-hours is equal to 360,000 Joules.
How do I convert Joules to Watt-hours?
Multiply the Joules value by 0.0002778 (or divide by 3,600).
Is this Watt-hours to Joules conversion exact?
Yes, exactly. Both units are fixed against the same base by definition, and 1 Watt-hour = 3,600 Joules is the complete value — nothing is rounded away.
What is a Watt-hour?
A watt-hour is energy, not power, and that distinction trips people up constantly. A watt is a rate — energy per second — so a watt-hour is what you get by sustaining that rate for an hour: a quantity of energy expressed as "this much power for this long". It is the natural unit for anything that stores energy and releases it gradually, which is why phone and laptop batteries are rated in watt-hours rather than the milliamp-hours stamped on the cell, and why airlines police lithium batteries by their watt-hour rating. Capacity in watt-hours tells you how long a load can run; watts alone never can.
What is a Joule?
The joule is the SI unit of energy and the reference every other energy unit here is defined against. One joule is one newton acting over one metre — push with a newton of force, move a metre, and you have spent a joule. It is named after James Prescott Joule, whose painstaking experiments established that heat and mechanical work are the same thing, measurable in the same units. That result sounds obvious now and was foundational then: it collapsed heat, motion and work into a single quantity called energy, which is why one unit can serve food, electricity, explosives and engines alike.