In 1 calorie [cal] [20°C] there is 0.0039659 BTU [ISO, British Thermal Unit].

atomic unit of energy [Eh] barrel of oil BTU [59°F, British Thermal Unit] BTU [international, British Thermal Unit] BTU [ISO, British Thermal Unit] BTU [mean, British Thermal Unit] BTU [thermochemical, British Thermal Unit] calorie [cal] [15°C] calorie [cal] [20°C] calorie [cal] [international 1929] calorie [cal] [international 1956] calorie [cal] [international] calorie [cal] [mean] calorie [cal] [thermochemical] celsius heat unit [CHU] [thermochemical] cubic foot of atmosphere cubic foot of natural gas cubic meter of atmosphere cubic yard of atmosphere electronvolt [eV] erg [erg] [CGS] foot pound [ft lbf] foot-pound force [ft lbf] foot-poundal [ft pdl] gallon atmosphere [gal atm] [imperial] gallon atmosphere [gal atm] [US] hartree [Eh] horsepower hour [hp h] inch-pound force [in lbf] joule [J] kilocalorie kilojoule large calorie [Gcal] liter atmosphere [l atm] megajoule millijoule quad rydberg [Ry] therm [EC] therm [US] thermie ton of coal ton of oil ton of tnt [tTNT] watt hour [Wh]

atomic unit of energy [Eh] barrel of oil BTU [59°F, British Thermal Unit] BTU [international, British Thermal Unit] BTU [ISO, British Thermal Unit] BTU [mean, British Thermal Unit] BTU [thermochemical, British Thermal Unit] calorie [cal] [15°C] calorie [cal] [20°C] calorie [cal] [international 1929] calorie [cal] [international 1956] calorie [cal] [international] calorie [cal] [mean] calorie [cal] [thermochemical] celsius heat unit [CHU] [thermochemical] cubic foot of atmosphere cubic foot of natural gas cubic meter of atmosphere cubic yard of atmosphere electronvolt [eV] erg [erg] [CGS] foot pound [ft lbf] foot-pound force [ft lbf] foot-poundal [ft pdl] gallon atmosphere [gal atm] [imperial] gallon atmosphere [gal atm] [US] hartree [Eh] horsepower hour [hp h] inch-pound force [in lbf] joule [J] kilocalorie kilojoule large calorie [Gcal] liter atmosphere [l atm] megajoule millijoule quad rydberg [Ry] therm [EC] therm [US] thermie ton of coal ton of oil ton of tnt [tTNT] watt hour [Wh]