Food labels, electric bills, and physics problems use joules, calories, kcal, Wh, kWh, and BTU. Convert energy units here.
kcal and food labels
Packaging “Calories” are usually kcal (~4184 J).
Kilowatt-hours
1 kWh = 3.6×10⁶ J—match meter readings to physics units.
BTU
Compare HVAC BTU ratings with kW or kcal.
Frequently asked questions
kcal to joules?
1 kcal ≈ 4184 J with standard factors—food labels’ “Calories” are usually kcal.
kWh vs joules?
1 kWh = 3.6×10⁶ J—convert meter readings and physics units here.
What is BTU?
HVAC ratings in North America may use BTU—compare with kW or kcal here.
Same as the calorie calculator?
This page converts energy units; the calorie calculator estimates daily needs from body stats.
Can I save my inputs?
Yes. Copy link below the form keeps your current inputs so you can share the scenario or save it for later.