Heat Flux Density Converter
Heat flux density is the rate of heat flow through a unit area. The SI unit is the watt per square metre (W/m²). Direct sunlight at the Earth’s surface on a clear day delivers roughly 1,000 W/m².
1 Watt/Meter² = 0.3169983306 BTU/Hour-Foot²
How to convert Watt/Meter² to BTU/Hour-Foot²
One Watt/Meter² equals 0.3169983306 BTU/Hour-Foot², so multiply any value in W/m² by 0.3169983306 to get BTU/(h·ft²). To convert back, divide by 0.3169983306 — or multiply by 3.154590745.
BTU/(h·ft²) = W/m² × 0.3169983306
Example: 25 W/m² × 0.3169983306 = 7.924958266 BTU/(h·ft²).
Watt/Meter² to BTU/Hour-Foot² table
| Watt/Meter² (W/m²) | BTU/Hour-Foot² (BTU/(h·ft²)) |
|---|---|
| 1 | 0.3169983306 |
| 2 | 0.6339966613 |
| 3 | 0.9509949919 |
| 4 | 1.267993323 |
| 5 | 1.584991653 |
| 10 | 3.169983306 |
| 15 | 4.754974959 |
| 20 | 6.339966613 |
| 25 | 7.924958266 |
| 50 | 15.84991653 |
| 75 | 23.7748748 |
| 100 | 31.69983306 |
| 250 | 79.24958266 |
| 500 | 158.4991653 |
| 1,000 | 316.9983306 |
BTU/Hour-Foot² to Watt/Meter² table
| BTU/Hour-Foot² (BTU/(h·ft²)) | Watt/Meter² (W/m²) |
|---|---|
| 1 | 3.154590745 |
| 2 | 6.30918149 |
| 3 | 9.463772235 |
| 4 | 12.61836298 |
| 5 | 15.77295373 |
| 10 | 31.54590745 |
| 15 | 47.31886118 |
| 20 | 63.0918149 |
| 25 | 78.86476863 |
| 50 | 157.7295373 |
| 75 | 236.5943059 |
| 100 | 315.4590745 |
| 250 | 788.6476863 |
| 500 | 1,577.295373 |
| 1,000 | 3,154.590745 |
Heat Flux Density units at a glance
All 9 units this converter supports, each expressed in Watt/Meter² (W/m²) and the other way round.
| Unit | Symbol | 1 unit in W/m² | 1 W/m² in unit |
|---|---|---|---|
| Watt/Meter² | W/m² | 1 | 1 |
| Kilowatt/Meter² | kW/m² | 1,000 | 0.001 |
| Watt/Centimeter² | W/cm² | 10,000 | 0.0001 |
| Watt/Inch² | W/in² | 1,550.0031 | 0.00064516 |
| Watt/Foot² | W/ft² | 10.76391042 | 0.09290304 |
| Calorie/Second-Centimeter² | cal/(s·cm²) | 41,840 | 0.00002390057361 |
| Kilocalorie/Hour-Meter² | kcal/(h·m²) | 1.163 | 0.8598452279 |
| BTU/Hour-Foot² | BTU/(h·ft²) | 3.154590745 | 0.3169983306 |
| HP/Foot² | hp/ft² | 8,026.646615 | 0.0001245850288 |
Where heat flux density conversions are used
Solar energy, fire and furnace engineering, building envelope analysis, and electronics cooling.
Frequently asked questions
What is 1 Watt/Meter² in BTU/Hour-Foot²?
1 Watt/Meter² (W/m²) is 0.3169983306 BTU/Hour-Foot² (BTU/(h·ft²)).
What is 1 BTU/Hour-Foot² in Watt/Meter²?
1 BTU/Hour-Foot² (BTU/(h·ft²)) is 3.154590745 Watt/Meter² (W/m²).
How do I convert Watt/Meter² to BTU/Hour-Foot²?
Multiply the value in Watt/Meter² by 0.3169983306. For example, 5 W/m² × 0.3169983306 = 1.584991653 BTU/(h·ft²). To go the other way, divide by 0.3169983306.
How many units does the heat flux density converter support?
It converts between 9 units: Watt/Meter², Kilowatt/Meter², Watt/Centimeter², Watt/Inch², Watt/Foot², Calorie/Second-Centimeter², Kilocalorie/Hour-Meter², BTU/Hour-Foot², HP/Foot².
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Figures on this page are calculated with the same conversion factors as the converter above and shown to up to 10 significant figures. See our disclaimer before relying on a result in a professional or safety-critical context.