Convert calorie to British thermal unit
1 cal = 0.003965666831 BTU
1 cal = 0.00397 BTU
1 cal in every energy unit
| joule | 4.18 J |
| kilojoule | 0.00418 kJ |
| megajoule | 0.00000418 MJ |
| calorie | 1 cal |
| kilocalorie | 0.001 kcal |
| watt-hour | 0.00116 Wh |
| kilowatt-hour | 0.00000116 kWh |
| British thermal unit | 0.00397 BTU |
| foot-pound | 3.09 ft⋅lb |
| electron volt | 2.61e+19 eV |
| kiloelectron volt | 2.61e+16 keV |
| megaelectron volt | 26,100,000,000,000 MeV |
How the conversion works
Multiply by 0.003965666831 to go from calorie to British thermal unit, or divide by it to go back. Every conversion on this site routes through the SI value (J) rather than a table of pairwise factors, so a round-trip returns exactly what you started with.
Going the other way? British thermal unit to calorie — 1 BTU = 252.1644007 cal.
calorie to British thermal unit — common values
| 1 cal | 0.0039656668 BTU |
| 2 cal | 0.0079313337 BTU |
| 3 cal | 0.011897 BTU |
| 5 cal | 0.019828334 BTU |
| 10 cal | 0.039656668 BTU |
| 15 cal | 0.059485002 BTU |
| 20 cal | 0.079313337 BTU |
| 25 cal | 0.099141671 BTU |
| 50 cal | 0.19828334 BTU |
| 75 cal | 0.29742501 BTU |
| 100 cal | 0.39656668 BTU |
| 250 cal | 0.99141671 BTU |
| 500 cal | 1.9828334 BTU |
| 1000 cal | 3.9656668 BTU |