Heat Density Converter
Heat density is the amount of energy delivered per unit of area — the time integral of heat flux. The SI unit is the joule per square meter. Solar and climate records use the langley, one thermochemical calorie per square centimeter, while US building energy work uses BTU per square foot.
9 units supported Base unit joule per square meter (J/m²)
Multiply the number of joules per square meter by 0.0000239005736138 to get langleys. How this is calculated
About heat density conversion
Heat Density conversion is commonly needed when solar insolation records, fire testing, and building energy models. One langley is one thermochemical calorie per square centimetre — the historic unit in solar radiation datasets.
Convert Joule per Square Meter to other heat density units
1 J/m² expressed in every other heat density unit on this site.
- Joule per Square Meter J/m² 1
- Kilojoule per Square Meter kJ/m² 0.001
- Megajoule per Square Meter MJ/m² 0.000001
- Watt-hour per Square Meter Wh/m² 0.00027777778
- Calorie (th) per Square Centimeter cal(th)/cm² 0.000023900574
- Langley Ly 0.000023900574
- Calorie (IT) per Square Centimeter cal(IT)/cm² 0.00002388459
- BTU (IT) per Square Foot BTU/ft² 0.000088055092
- BTU (th) per Square Foot BTU(th)/ft² 0.00008811402
Complete list of heat density units
All 9 units this converter supports, each stated against the joule per square meter (J/m²).
| Unit | Symbol | System | In joules per square meter | Conversions |
|---|---|---|---|---|
| Joule per Square Meter | J/m² | SI | base unit (J/m²) | — |
| Kilojoule per Square Meter | kJ/m² | SI | 1 kJ/m² = 1,000 J/m² | — |
| Megajoule per Square Meter | MJ/m² | SI | 1 MJ/m² = 1,000,000 J/m² | — |
| Watt-hour per Square Meter | Wh/m² | SI | 1 Wh/m² = 3,600 J/m² | — |
| Calorie (th) per Square Centimeter | cal(th)/cm² | Metric | 1 cal(th)/cm² = 41,840 J/m² | — |
| Langley | Ly | Other | 1 Ly = 41,840 J/m² | — |
| Calorie (IT) per Square Centimeter | cal(IT)/cm² | Metric | 1 cal(IT)/cm² = 41,868 J/m² | — |
| BTU (IT) per Square Foot | BTU/ft² | Imperial | 1 BTU/ft² = 11,356.5266822 J/m² | — |
| BTU (th) per Square Foot | BTU(th)/ft² | Imperial | 1 BTU(th)/ft² = 11,348.9317948 J/m² | — |
No unit in this category matches that search.
Scroll the table sideways to see every column.
Frequently asked questions
What is the base unit for heat density?
Heat Density conversions on this site are calculated against the joule per square meter (J/m²).
Which heat density units can I convert?
You can convert between 9 units, including joule per square meter, kilojoule per square meter, megajoule per square meter, watt-hour per square meter, and more.
Where is heat density conversion useful?
It is commonly needed when solar insolation records, fire testing, and building energy models.
Does this converter mix measurement systems?
The converter supports SI, Metric, Other, Imperial units and keeps their exact definitions separate so results stay accurate.
Related categories
Conversion factors are based on internationally agreed unit definitions. See our methodology and sources for details on how these values are verified.