Marks Calc

kilojoules to joules

Convert kilojoule to joule — instant, free, with the formula shown.

1 kJ=1000 J

How to convert kilojoule to joule

To convert kilojoule to joule, multiply by 1000:

J = kJ × 1000

For example, 10 kJ × 1000 = 10000 J.

kJ to J conversion table

kilojoules (kJ)joules (J)
1 kJ1000 J
2 kJ2000 J
5 kJ5000 J
10 kJ10000 J
25 kJ25000 J
50 kJ50000 J
100 kJ100000 J
250 kJ250000 J
500 kJ500000 J
1000 kJ1000000 J
Reverse: Joule to Kilojoule

Other kilojoule conversions

Convert to joule from another unit

kJ to J — frequently asked

How many joules are in 1 kilojoule?

1 kilojoule = 1000 joules (kJ × 1000 = J).

What is the formula to convert kilojoule to joule?

Multiply your kilojoule value by 1000 to get joule.

How do I convert 10 kilojoules to joules?

10 kJ = 10000 J. For 100 kJ the answer is 100000 J. Use the calculator on this page for any other value.

When to convert kilojoule to joule

1Electricity bills (kWh)
2Nutrition labels (kcal / food cal)
3HVAC and heating (BTU, therms)
4Physics and chemistry (J, eV)

Energy conversion — common questions

Is a food calorie the same as a calorie?

No — a food 'Calorie' (capital C) actually means 1 kilocalorie = 1,000 small calories = 4,184 J. Nutrition labels typically write 'cal' meaning kcal.

How many joules in 1 kWh?

1 kWh = 3,600,000 J (3.6 MJ). Because 1 kW × 1 hour = 1,000 W × 3,600 s = 3,600,000 J.

What is a BTU?

British Thermal Unit — the energy required to raise 1 pound of water by 1 °F. 1 BTU ≈ 1,055 J.

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