Energy converter
Energy Converter – 11 Units, Exact Factors
1 kilocalorie (food Calorie) = 4.184 kilojoules
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- 1 kcal = 4.184 kJ
- 5 kcal = 20.92 kJ
- 10 kcal = 41.84 kJ
- 25 kcal = 104.6 kJ
- JoulesJ
- KilojouleskJ
- MegajoulesMJ
- Caloriescal
- Kilocalorieskcal
- Watt-hoursWh
- Kilowatt-hourskWh
- British thermal unitsBTU
- Therms (US)thm
- Foot-poundsft·lbf
- ElectronvoltseV
- Joules4,184J
- Kilojoules4.184kJ
- Megajoules0.004184MJ
- Calories1,000cal
- Kilocalories1kcal
- Watt-hours1.1622Wh
- Kilowatt-hours0.0011622kWh
- British thermal units3.9657BTU
- Therms (US)0.000039666thm
- Foot-pounds3,086ft·lbf
- ElectronvoltseV
About energy conversions
From food Calories to electricity bills. A food Calorie is one kilocalorie (4.184 kJ).
Common energy conversions
Energy units explained
| Unit | System | Definition and notes |
|---|---|---|
| Joule (J) | SI (metric) | Base unit |
| Kilojoule (kJ) | SI (metric) | 1 kJ = 1,000 J (exact) |
| Megajoule (MJ) | SI (metric) | 1 MJ = 1,000,000 J (exact) |
| Calorie (thermochemical) (cal) | other | 1 cal = 4.184 J (exact)The small calorie used in chemistry: exactly 4.184 J. |
| Kilocalorie (food Calorie) (kcal) | other | 1 kcal = 4,184 J (exact)Exactly 4,184 J. The "Calorie" on food labels is one of these. |
| Watt-hour (Wh) | other | 1 Wh = 3,600 J (exact) |
| Kilowatt-hour (kWh) | other | 1 kWh = 3,600,000 J (exact)Defined as exactly 3.6 MJ. The unit on electricity bills. |
| British thermal unit (IT) (BTU) | US & imperial (identical) | 1 BTU = 1,055.05585262 J (exact)The British thermal unit (International Table version): exactly 1,055.05585262 J. |
| Therm (US) (thm) | US customary | 1 thm = 105,480,400 J (exact)The US therm: exactly 105,480,400 J (about 100,000 BTU). Used on natural-gas bills. |
| Foot-pound (energy) (ft·lbf) | US & imperial (identical) | 1 ft·lbf ≈ 1.3558179 J |
| Electronvolt (eV) | other | 1 eV = 1.602176634 × 10⁻¹⁹ J (exact)The energy one electron gains across 1 volt: exactly 1.602176634 × 10⁻¹⁹ J. |
Kilocalories to kilojoules conversion table
| Kilocalories (kcal) | Kilojoules (kJ) |
|---|---|
| 0.1 kcal | 0.4184 kJ |
| 0.5 kcal | 2.092 kJ |
| 1 kcal | 4.184 kJ |
| 2 kcal | 8.368 kJ |
| 3 kcal | 12.552 kJ |
| 4 kcal | 16.736 kJ |
| 5 kcal | 20.92 kJ |
| 6 kcal | 25.104 kJ |
| 7 kcal | 29.288 kJ |
| 8 kcal | 33.472 kJ |
| 9 kcal | 37.656 kJ |
| 10 kcal | 41.84 kJ |
| 15 kcal | 62.76 kJ |
| 20 kcal | 83.68 kJ |
| 25 kcal | 104.6 kJ |
| 30 kcal | 125.52 kJ |
| 40 kcal | 167.36 kJ |
| 50 kcal | 209.2 kJ |
| 75 kcal | 313.8 kJ |
| 100 kcal | 418.4 kJ |
| 250 kcal | 1,046 kJ |
| 500 kcal | 2,092 kJ |
| 1,000 kcal | 4,184 kJ |
Frequently asked questions
Which energy units can I convert?
joules (J), kilojoules (kJ), megajoules (MJ), calories (cal), kilocalories (kcal), watt-hours (Wh), kilowatt-hours (kWh), British thermal units (BTU), therms (thm), foot-pounds (ft·lbf), electronvolts (eV).
How accurate are the results?
Every unit is stored with its exact defining factor (NIST SP 811, NIST Handbook 44 or the BIPM SI Brochure). Calculations use double-precision arithmetic and are rounded only for display, to 5 significant figures by default (trailing zeros dropped, so 1 km shows as 1000 m). You can choose Auto (up to 10 digits), fixed decimals or more significant figures, or switch to scientific or engineering notation.