1 joule (j) is equal to 0.0002778 watt-hours (wh).
This conversion shows how energy measured in joules relates to the watt-hour unit, which represents the energy consumption over time. Because a watt-hour equals 3600 joules, converting from joules to watt-hours involves dividing the joule value by 3600.
Conversion Tool
Result in wh:
Conversion Formula
The formula to convert joules (j) to watt-hours (wh) is:
wh = j ÷ 3600
This works because 1 watt-hour equals 3600 joules. A joule is a unit of energy, and watt-hour measures energy as power multiplied by time (watts × hours). Since 1 watt is 1 joule per second, multiplying watts by hours (3600 seconds) results in 3600 joules per watt-hour.
Example: To convert 7200 j to wh:
- Divide 7200 j by 3600
- 7200 ÷ 3600 = 2 wh
Conversion Example
- Convert 1800 j to wh:
- Step 1: Take the joule value 1800
- Step 2: Divide by 3600 (seconds in an hour)
- 1800 ÷ 3600 = 0.5 wh
- Result: 1800 j equals 0.5 wh
- Convert 5400 j to wh:
- 5400 ÷ 3600 = 1.5 wh
- So 5400 joules is 1.5 watt-hours
- Convert 900 j to wh:
- 900 ÷ 3600 = 0.25 wh
- Therefore, 900 j equals 0.25 wh
- Convert 36000 j to wh:
- 36000 ÷ 3600 = 10 wh
- Thus, 36000 joules equals 10 watt-hours
Conversion Chart
| Joules (j) | Watt-hours (wh) |
|---|---|
| -24.0 | -0.0067 |
| -20.0 | -0.0056 |
| -16.0 | -0.0044 |
| -12.0 | -0.0033 |
| -8.0 | -0.0022 |
| -4.0 | -0.0011 |
| 0.0 | 0.0000 |
| 2.0 | 0.0006 |
| 6.0 | 0.0017 |
| 10.0 | 0.0028 |
| 14.0 | 0.0039 |
| 18.0 | 0.0050 |
| 22.0 | 0.0061 |
| 26.0 | 0.0072 |
The chart shows joule values between -24 and 26 and their converted watt-hour equivalents by dividing each joule value by 3600. You can quickly find the wh value for a joule input by locating it in the left column and reading across.
Related Conversion Questions
- How many watt-hours are in 1 joule?
- What is the exact formula to convert 1 j to wh?
- Why does dividing joules by 3600 give watt-hours?
- Is 1 joule a large or small amount of energy compared to watt-hours?
- How to convert 1 j to wh in a calculator?
- Can 1 j be expressed as a decimal in watt-hours?
- What unit conversions are needed to go from j to wh?
Conversion Definitions
j (joule): A joule is the SI unit of energy, defined as the work done when a force of one newton moves an object one meter in the force’s direction. It measures energy, work, or amount of heat in physics and engineering contexts.
wh (watt-hour): A watt-hour is a unit of energy representing the amount of work done by power of one watt operating for one hour. It is commonly used to measure electrical energy consumption or storage capacity.
Conversion FAQs
Does converting 1 joule to watt-hours lose precision?
Since 1 joule is a very small energy amount compared to a watt-hour, converting 1 j to wh results in a small decimal (0.0002778 wh). Precision can be affected by rounding, especially when showing only a few decimal places, but the exact ratio remains constant.
Can negative joule values be converted to watt-hours?
Yes, negative joules indicate energy loss or output; converting negative joules to watt-hours by dividing by 3600 will give negative wh values, showing energy released or consumed instead of stored.
Why divide joules by 3600 to get watt-hours?
Because 1 watt equals 1 joule per second, and an hour has 3600 seconds, 1 watt-hour equals 3600 joules. So to get wh from joules, you divide joules by 3600 to account for the seconds-to-hours conversion.
Is watt-hour a better unit for electrical billing than joule?
Yes, watt-hours are more practical for billing and measuring electricity use over time. Joules are small and less intuitive for everyday energy consumption, while watt-hours relate power use to time, matching how electricity usage is tracked.
Can I convert watt-hours back to joules easily?
Yes, converting watt-hours back to joules is done by multiplying the wh value by 3600. This reverses the division used in j to wh conversion, restoring the base energy measurement.