Energy Converter
Convert electrical, heat, and mechanical energy units.
Choose units
Enter a value, pick the units, and the conversion updates instantly.
Quick converter. Results update locally in your browser.
Conversion notes
Companion units, sanity checks, and precision notes.
What this means
1 kilowatt-hours converts to 3,600,000 joules. The reverse check is 1 kilowatt-hours, which is useful for spotting unit-entry mistakes.
Copy result
Copy a short conversion note for your own worksheet. CalcShelf does not save the input.
| Unit | Converted value | Based on |
|---|---|---|
| joules | 3,600,000 joules | 1 kilowatt-hours |
| kilojoules | 3,600 kilojoules | 1 kilowatt-hours |
| watt-hours | 1,000 watt-hours | 1 kilowatt-hours |
| kilowatt-hours | 1 kilowatt-hours | 1 kilowatt-hours |
| BTU | 3,412.14 BTU | 1 kilowatt-hours |
- Converted value
- 3,600,000 joules
- Based on
- 1 kilowatt-hours
- Converted value
- 3,600 kilojoules
- Based on
- 1 kilowatt-hours
- Converted value
- 1,000 watt-hours
- Based on
- 1 kilowatt-hours
- Converted value
- 1 kilowatt-hours
- Based on
- 1 kilowatt-hours
- Converted value
- 3,412.14 BTU
- Based on
- 1 kilowatt-hours
Energy planning comparison
Use these local-only rows when the conversion feeds a battery, electric bill, heat load, duty-cycle, or equipment-sizing conversation instead of a one-off unit translation.
| Scenario | kWh | Wh | MJ | BTU | Use it for |
|---|---|---|---|---|---|
| Entered energy | 1 | 1,000 | 3.6 | 3,412.14 | Use this row to keep the source energy value visible across electrical, heat, and mechanical units. |
| 80% usable energy | 0.8 | 800 | 2.88 | 2,729.71 | Quick derating check for batteries, inverters, storage losses, or equipment where not all rated energy is usable. |
| Add 20% reserve | 1.2 | 1,200 | 4.32 | 4,094.57 | Planning buffer for uncertain duty cycle, conversion losses, cold-weather battery performance, or early sizing conversations. |
| Daily use for 30 days | 30 | 30,000 | 108 | 102,364.25 | Monthly reference if the entered energy is a typical daily use, charge, heating load, or work cycle. |
- kWh
- 1
- Wh
- 1,000
- MJ
- 3.6
- BTU
- 3,412.14
- Use it for
- Use this row to keep the source energy value visible across electrical, heat, and mechanical units.
- kWh
- 0.8
- Wh
- 800
- MJ
- 2.88
- BTU
- 2,729.71
- Use it for
- Quick derating check for batteries, inverters, storage losses, or equipment where not all rated energy is usable.
- kWh
- 1.2
- Wh
- 1,200
- MJ
- 4.32
- BTU
- 4,094.57
- Use it for
- Planning buffer for uncertain duty cycle, conversion losses, cold-weather battery performance, or early sizing conversations.
- kWh
- 30
- Wh
- 30,000
- MJ
- 108
- BTU
- 102,364.25
- Use it for
- Monthly reference if the entered energy is a typical daily use, charge, heating load, or work cycle.
Energy-spec checklist
| Check | Why |
|---|---|
| Separate power from energy | Watts and horsepower are rates; watt-hours, kWh, joules, and BTU are accumulated energy over time. |
| Write down the time basis | A daily cycle, one charge, one heating run, and one month of use can all be correct but mean different totals. |
| Apply efficiency and usable-capacity limits | Batteries, inverters, heaters, motors, and mechanical systems rarely deliver every rated joule to useful work. |
- Why
- Watts and horsepower are rates; watt-hours, kWh, joules, and BTU are accumulated energy over time.
- Why
- A daily cycle, one charge, one heating run, and one month of use can all be correct but mean different totals.
- Why
- Batteries, inverters, heaters, motors, and mechanical systems rarely deliver every rated joule to useful work.
Watch-outs
- Make sure the source and destination units are from the same measurement family.
- Do not use a quick conversion as final design approval for safety-critical systems.
- Confirm standards, tolerances, temperature, material condition, and manufacturer data where specs matter.
Rounded for quick checks. For regulated, safety-critical, or tolerance-sensitive work, verify the required precision before using the number.
Example
1 kWh = 3,600,000 joules.
Notes
Results are rounded for quick checks. Use official specs or calibrated tools when tolerances, compliance, or safety matter.
Use the Energy Converter without guessing what to do next
- Start with the example values to see what the main result looks like.
- Replace the example values with the best numbers you have right now; rough estimates are fine for a first pass.
- Change one input at a time so you can see which assumption actually moves the answer.
What the result means
The result is a quick technical check based on a standard formula or unit relationship. It helps you sanity-check a spec before deeper review.
How to use it
Use it to catch order-of-magnitude problems: a value that is wildly too high, too low, or in the wrong unit before it reaches a drawing, quote, or part list.
What can change it
Do not treat a simple calculator as engineering approval. Real equipment decisions can depend on tolerance, safety factor, code, heat, duty cycle, and manufacturer limits.
Good for
Convert electricity and heat energy units.
Check this next
Try Power Converter, Ohm’s Law Voltage Calculator, Data Storage Converter to cross-check the same decision from another angle.
Best habit
Run a conservative case and an optimistic case. The gap between them is often more useful than a single answer.
Common uses
- Convert electricity and heat energy units.
- Compare kWh, BTU, and joules.
- Translate energy specs quickly.
Common questions
Is the Energy Converter private?
CalcShelf calculators run without an account. Your entries stay in the calculator while you work; CalcShelf does not save them or place your numbers in shareable links.
How accurate is the Energy Converter?
It is a formula check, not stamped engineering. Tolerance, safety factor, heat, duty cycle, environment, and manufacturer limits can change real equipment choices.
What should I check after using the Energy Converter?
Verify units, specs, tolerances, safety factors, code requirements, and manufacturer data before choosing parts or equipment.
Which calculator should I try next?
Try Power Converter, Ohm’s Law Voltage Calculator, Data Storage Converter as next checks so you can compare the same decision from another angle before acting.
Method behind the estimate
Engineering tools use standard unit relationships and simple mechanical, electrical, pressure, energy, density, or flow conversions.
Why the detail matters
For design, safety, warranty, or production work, verify against official specifications, standards, tolerances, and qualified engineering review.
No account or saved inputs
Your calculator values are for your session. CalcShelf does not require an account, save calculator entries, or add your numbers to shareable URLs.
Copy or print safely
Use any copy, print, or worksheet controls as local handoff tools for your own notes, supplier calls, lender questions, or implementation checklist. They are there to help you explain the result to a human.
Before acting
Treat the result as a decision draft, not a verdict. Recheck the source numbers, run a downside case, and verify the real-world rule, quote, label, or spec that controls the final answer.
Last reviewed: May 11, 2026. See methodology and editorial policy for formulas, assumptions, rounding, review approach, and limitations. For production, code, safety, or equipment changes, verify against official specs.