Energy Conversion Chart
Quick-reference energy conversion chart. The tables below compare the most common units side by side. Download the free PDF for offline and printable use.
Standards and method
Values are calculated from the shared conversion-factor library. Exact defined relationships are preserved; displayed results are rounded only for readability.
Maintained by Miguel Coelho. Updated . See our editorial policy.
Printable energy conversion chart
Joules, kWh, calories, BTU and therms. Includes the exact definition, formulas, a worked example and sources. Conversion values are checked against the defining constants, and reference data is cited to its source, before the PDF is published.
Free to print, share and use in teaching materials with attribution (CC BY 4.0).
Also in the HVAC and Refrigeration Reference Pack, with related sheets in one PDF.
Energy Conversion Table
| Unit | per 1 J | per 1 kWh | per 1 BTU |
|---|---|---|---|
| Joule (J) | 1 J | 3600000 J | 1055.06 J |
| Kilojoule (kJ) | 0.001 kJ | 3600 kJ | 1.05506 kJ |
| Megajoule (MJ) | 1.0000e-6 MJ | 3.6 MJ | 0.00105506 MJ |
| Calorie (cal) | 0.239006 cal | 860421 cal | 252.164 cal |
| Kilocalorie (kcal) | 0.000239006 kcal | 860.421 kcal | 0.252164 kcal |
| Watt Hour (Wh) | 0.000277778 Wh | 1000 Wh | 0.293071 Wh |
| Kilowatt Hour (kWh) | 2.7778e-7 kWh | 1 kWh | 0.000293071 kWh |
| British Thermal Unit (BTU) | 0.000947817 BTU | 3412.14 BTU | 1 BTU |
| Therm (thm) | 9.4782e-9 thm | 0.0341214 thm | 1.0000e-5 thm |
Values are calculated from the shared conversion-factor library. Exact defined relationships are preserved; displayed results are rounded only for readability.
Full energy conversion chart
Joules, kWh, calories, BTU and therms. These are the same tables as the printable PDF. For: Engineers, students, energy auditors and nutrition.
- Exact definition
- 1 kWh = 3.6 MJ; 1 kcal = 4.184 kJ; 1 BTU = 1,055.055 852 62 J
- Formula
- MJ = kWh × 3.6; kJ = kcal × 4.184
- Reverse
- kWh = MJ ÷ 3.6; kcal = kJ ÷ 4.184
- Worked example
- 1 therm = 100,000 BTU = 29.307 kWh
- Rounding
- Matrix values use 6 significant figures. Calories are thermochemical (4.184 J); food labels use kcal.
Conversion factor matrix
Read across: 1 unit in the left column equals the value shown in each column unit.
| 1 unit = | J | kJ | MJ | kcal | Wh | kWh | BTU | thm |
|---|---|---|---|---|---|---|---|---|
| 1 J | 1 | 0.001 | 1 × 10⁻⁶ | 2.39006 × 10⁻⁴ | 2.77778 × 10⁻⁴ | 2.77778 × 10⁻⁷ | 9.47817 × 10⁻⁴ | 9.47817 × 10⁻⁹ |
| 1 kJ | 1,000 | 1 | 0.001 | 0.239006 | 0.277778 | 2.77778 × 10⁻⁴ | 0.947817 | 9.47817 × 10⁻⁶ |
| 1 MJ | 1 × 10⁶ | 1,000 | 1 | 239.006 | 277.778 | 0.277778 | 947.817 | 0.00947817 |
| 1 kcal | 4,184 | 4.184 | 0.004184 | 1 | 1.16222 | 0.00116222 | 3.96567 | 3.96567 × 10⁻⁵ |
| 1 Wh | 3,600 | 3.6 | 0.0036 | 0.860421 | 1 | 0.001 | 3.41214 | 3.41214 × 10⁻⁵ |
| 1 kWh | 3.6 × 10⁶ | 3,600 | 3.6 | 860.421 | 1,000 | 1 | 3,412.14 | 0.0341214 |
| 1 BTU | 1,055.06 | 1.05506 | 0.00105506 | 0.252164 | 0.293071 | 2.93071 × 10⁻⁴ | 1 | 1 × 10⁻⁵ |
| 1 thm | 1.05506 × 10⁸ | 105,506 | 105.506 | 25,216.4 | 29,307.1 | 29.3071 | 100,000 | 1 |
Kilowatt-hours to megajoules, BTU and therms
| Kilowatt-hours (kWh) | Megajoules (MJ) | British thermal units (BTU) | Therms (thm) |
|---|---|---|---|
| 1 | 3.6 | 3,412 | 0.034 |
| 2 | 7.2 | 6,824 | 0.068 |
| 3 | 10.8 | 10,236 | 0.102 |
| 4 | 14.4 | 13,649 | 0.136 |
| 5 | 18.0 | 17,061 | 0.171 |
| 6 | 21.6 | 20,473 | 0.205 |
| 7 | 25.2 | 23,885 | 0.239 |
| 8 | 28.8 | 27,297 | 0.273 |
| 9 | 32.4 | 30,709 | 0.307 |
| 10 | 36.0 | 34,121 | 0.341 |
| 15 | 54.0 | 51,182 | 0.512 |
| 20 | 72.0 | 68,243 | 0.682 |
| 25 | 90.0 | 85,304 | 0.853 |
| 50 | 180.0 | 170,607 | 1.706 |
| 100 | 360.0 | 341,214 | 3.412 |
| 250 | 900.0 | 853,035 | 8.530 |
| 500 | 1,800.0 | 1,706,071 | 17.061 |
| 1,000 | 3,600.0 | 3,412,142 | 34.121 |
Food energy: kilocalories to kilojoules
| Kilocalories (kcal) | Kilojoules (kJ) |
|---|---|
| 50 | 209 |
| 100 | 418 |
| 150 | 628 |
| 200 | 837 |
| 250 | 1,046 |
| 300 | 1,255 |
| Kilocalories (kcal) | Kilojoules (kJ) |
|---|---|
| 350 | 1,464 |
| 400 | 1,674 |
| 450 | 1,883 |
| 500 | 2,092 |
| 600 | 2,510 |
| 750 | 3,138 |
| Kilocalories (kcal) | Kilojoules (kJ) |
|---|---|
| 1,000 | 4,184 |
| 1,500 | 6,276 |
| 2,000 | 8,368 |
| 2,500 | 10,460 |
| 3,000 | 12,552 |
Sources for this chart
Conversion values on this sheet are generated by the AllUnitConversions conversion library and automatically checked against the exact definitions above before the PDF is produced; reference tables are taken from the sources listed.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
- BIPM SI Brochure, 9th edition — Definitions of the SI units, including the kelvin
Related Converters & Charts
Energy Conversion Chart FAQs
Common questions about the energy conversion chart.
What does this energy conversion chart include?
It lists the most common energy units side by side with their conversion factors, plus a free printable PDF you can download for offline reference.
What exact definition is this energy chart based on?
1 kWh = 3.6 MJ; 1 kcal = 4.184 kJ; 1 BTU = 1,055.055 852 62 J. Formula: MJ = kWh × 3.6; kJ = kcal × 4.184. Matrix values use 6 significant figures. Calories are thermochemical (4.184 J); food labels use kcal.
Can I download this chart as a PDF, CSV, or JSON?
Yes. Use the Download A4 PDF or US Letter PDF buttons for a printable version, or download the same tables as CSV or JSON from the links on this page.