The calculation, without hidden assumptions
Energy units come from electrical billing, thermodynamics, nutrition, mechanics and particle physics. A kilowatt-hour, a food Calorie, a BTU and an electronvolt all represent energy, but their magnitudes span enormous ranges. MAXScanner converts every supported unit through joules, supports scientific notation for extreme scales, distinguishes the thermochemical calorie from the food kilocalorie, and links to the existing Joules↔Wh and kWh↔MJ calculators when the user wants those specialized reciprocal relationships.
How to use this calculator
Enter the energy value and select the unit used by the bill, label, physics problem or specification.
Choose the target unit and use Auto or Scientific notation when electronvolts and macroscopic energy units produce very large exponent differences.
Use the all-unit comparison to check joules, electrical energy, food-energy and thermal units without confusing power units such as watts or BTU/h with energy.
Where people use it
- •Electricity and battery energy comparisons
- •HVAC and thermal-energy documents
- •Food-label kJ/kcal conversion
- •Physics and particle-energy calculations
Example: 1 kWh in joules and BTU
One kilowatt-hour is exactly 3,600,000 joules or 3.6 MJ. Using the International Table BTU factor, the same energy is about 3,412.14 BTU.
What the result does not assume
- •kW and kWh are different quantities: kW is power, while kWh is energy accumulated over time.
- •“Calorie” can be ambiguous in everyday language. This converter labels scientific thermochemical calorie (cal) and food kilocalorie (kcal) separately.
Frequently asked questions
How many joules are in one kWh?+
Exactly 3,600,000 joules.
How many BTU are in one kWh?+
Using the International Table BTU, one kWh is about 3,412.14 BTU.
Is one food Calorie equal to one calorie?+
No. A food Calorie is conventionally one kilocalorie, or 1,000 thermochemical calories, equal to 4,184 J.
Can I convert watts to joules here?+
Not without a time interval. Watts are power (J/s); use an energy-over-time calculation when converting between power and energy.
Semantic next steps
Continue the calculation
These links move to a different input, formula or project stage rather than a keyword variation of this page.
Power Unit Converter — W, kW, MW, HP, PS, BTU/h & Refrigeration Tons
Convert power between W, mW, kW, MW, GW, mechanical hp, metric PS, BTU/h, kcal/h, refrigeration tons and ft·lbf/s, with all equivalents and explicit power-vs-energy guidance.
OpenJoules ↔ Watt-Hours Calculator — J, kJ, MJ, Wh & kWh
Convert joules to watt-hours or watt-hours to joules using the exact 3,600 J per Wh relationship, with kJ, MJ, Wh and kWh equivalents plus visible reciprocal working.
OpenkWh ↔ MJ Calculator — Kilowatt-Hours & Megajoules
Convert kilowatt-hours to megajoules or megajoules to kilowatt-hours with the exact 1 kWh = 3.6 MJ relationship, plus joule, kilojoule and watt-hour equivalents.
OpenElectricity Cost Calculator — kWh & Energy Cost
Estimate energy use in kWh and simple electricity cost from device watts, hours per day, number of days and your own tariff per kWh.
OpenBattery Runtime Calculator — Wh/Ah, Load, DoD & Efficiency
Estimate battery runtime from Wh or Ah capacity, voltage, load, usable depth of discharge and conversion efficiency, while keeping ideal and adjusted runtime separate.
OpenAh ↔ Wh Calculator — Battery Charge & Energy
Convert amp-hours to watt-hours or watt-hours to amp-hours using battery voltage, with kWh and mAh equivalents and a reverse check on the same page.
OpenPressure Converter — PSI, Bar, kPa, MPa, atm, Torr & mmHg
Convert pressure instantly between Pa, hPa, kPa, MPa, GPa, bar, mbar, psi, ksi, atm, Torr, mmHg, inHg and kgf/cm², with every equivalent, the direct factor, adjustable precision and gauge-vs-absolute guidance.
OpenTorque Unit Converter — N·m, lb·ft, lb·in, oz·in & kgf·m
Convert torque between N·m, kN·m, mN·m, lbf·ft, lbf·in, ozf·in, kgf·m, kgf·cm and gf·cm with every equivalent, adjustable precision and a direct conversion factor.
OpenMore in this calculator collection
Browse nearby calculators in the same topic cluster so related pages reinforce each other instead of sitting as isolated URLs.
Free publisher widget
Put this calculator on your website
Give readers the live calculator without rebuilding the math. Copy the responsive embed in one click, or customize width, height, border and corner radius before publishing. The branded MAXScanner attribution stays visible.
Keep the result connected to the real job
MAXScanner keeps the formula and assumptions beside the result so you can verify the number before using it in a drawing, estimate, specification, worksheet or document. Where a supplier, manufacturer, drawing or applicable standard owns a requirement, that source remains authoritative.