Heat Density Converter
Convert heat or energy per area between J/m², kJ/m², MJ/m², kWh/m², BTU/ft² and langleys.
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Result
Heat Density units
Every unit below converts to every other one in the calculator. Values are relative to the base unit, the joule per square meter (J/m²).
| Unit | Symbol | System | Value |
|---|---|---|---|
| Joule per square meter | J/m² | SI | Base unit |
| Kilojoule per square meter | kJ/m² | SI | = 1000 J/m² |
| Megajoule per square meter | MJ/m² | SI | = 1000000 J/m² |
| Kilowatt-hour per square meter | kWh/m² | SI-accepted | = 3600000 J/m² |
| BTU per square foot | BTU/ft² | US customary | ≈ 11356.52668 J/m² |
| Langley | Ly | other | = 41840 J/m² |
Joule per square meter quick reference
| Joule per square meter | Kilojoule per square meter | Megajoule per square meter | Kilowatt-hour per square meter |
|---|---|---|---|
| 1 J/m² | = 0.001 kJ/m² | = 0.000001 MJ/m² | ≈ 2.777777778e-7 kWh/m² |
| 10 J/m² | = 0.01 kJ/m² | = 0.00001 MJ/m² | ≈ 0.000002777777778 kWh/m² |
| 100 J/m² | = 0.1 kJ/m² | = 0.0001 MJ/m² | ≈ 0.00002777777778 kWh/m² |
| 1000 J/m² | = 1 kJ/m² | = 0.001 MJ/m² | ≈ 0.0002777777778 kWh/m² |
Among the 6 heat density units on this page, the smallest is the joule per square meter (J/m²) and the largest is the kilowatt-hour per square meter (kWh/m²).
More heat density conversions
About heat density units
Heat density here means energy received or released per unit area, such as the solar energy that falls on a surface during a day. Its SI unit is the joule per square meter (J/m²). It is heat flux (W/m²) added up over time.
One kWh/m² is exactly 3.6 MJ/m². The langley, found in older solar radiation data, is one thermochemical calorie per square centimeter, exactly 41,840 J/m². One BTU/ft² is about 11.357 kJ/m².
Frequently asked questions
- How do I convert kWh/m² to MJ/m²?
- Multiply by 3.6. For example, 5 kWh/m² of daily sunshine is 18 MJ/m².
- What is the difference between W/m² and kWh/m²?
- W/m² is a rate (power per area); kWh/m² is an amount (energy per area). 1000 W/m² sustained for one hour delivers 1 kWh/m².
- How many langleys are in 1 MJ/m²?
- About 23.901 langleys, since one langley is exactly 0.04184 MJ/m².
- How many kilojoules per square meter are in one joule per square meter?
- One joule per square meter = 0.001 kJ/m² (kilojoules per square meter).
- How many megajoules per square meter are in one joule per square meter?
- One joule per square meter = 0.000001 MJ/m² (megajoules per square meter).
- How many kilowatt-hours per square meter are in one joule per square meter?
- One joule per square meter ≈ 2.777777778e-7 kWh/m² (kilowatt-hours per square meter).