BTU per hour square foot to Watts per square metre
Convert BTU per hour square foot to watts per square metre instantly.
BTU per hour square foot to Watts per square metre (BTU/(h·ft²) to W/m²) Converter
1 BTU per hour square foot = 3.1546 watts per square metre
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- 1 BTU/(h·ft²) = 3.1546 W/m²
- 5 BTU/(h·ft²) = 15.773 W/m²
- 10 BTU/(h·ft²) = 31.546 W/m²
- 25 BTU/(h·ft²) = 78.865 W/m²
- Watts per square metreW/m²
- BTU per hour square footBTU/(h·ft²)
- Watts per square metreW/m²
- BTU per hour square footBTU/(h·ft²)
How it’s calculated
W/m² = BTU/(h·ft²) × 3.154590745
- Multiply the value in BTU per hour square foot by 3.154590745.
- To go back, divide by 3.154590745 (or multiply by 0.3169983306).
- 1 BTU/(h·ft²) = 3.154590745 W/m² · 1 W/m² = 0.3169983306 BTU/(h·ft²)
Quick examples
1 BTU per hour square foot = 3.1546 watts per square metre · 1 W/m² = 0.317 BTU/(h·ft²)
- 1 BTU per hour square foot = 3.1546 watts per square metre
- 5 BTU per hour square foot = 15.773 watts per square metre
- 10 BTU per hour square foot = 31.546 watts per square metre
- 25 BTU per hour square foot = 78.865 watts per square metre
- 100 BTU per hour square foot = 315.46 watts per square metre
BTU per hour square foot to watts per square metre conversion table
| BTU per hour square foot (BTU/(h·ft²)) | Watts per square metre (W/m²) |
|---|---|
| 0.1 BTU/(h·ft²) | 0.31546 W/m² |
| 0.5 BTU/(h·ft²) | 1.5773 W/m² |
| 1 BTU/(h·ft²) | 3.1546 W/m² |
| 2 BTU/(h·ft²) | 6.3092 W/m² |
| 3 BTU/(h·ft²) | 9.4638 W/m² |
| 4 BTU/(h·ft²) | 12.618 W/m² |
| 5 BTU/(h·ft²) | 15.773 W/m² |
| 6 BTU/(h·ft²) | 18.928 W/m² |
| 7 BTU/(h·ft²) | 22.082 W/m² |
| 8 BTU/(h·ft²) | 25.237 W/m² |
| 9 BTU/(h·ft²) | 28.391 W/m² |
| 10 BTU/(h·ft²) | 31.546 W/m² |
| 15 BTU/(h·ft²) | 47.319 W/m² |
| 20 BTU/(h·ft²) | 63.092 W/m² |
| 25 BTU/(h·ft²) | 78.865 W/m² |
| 30 BTU/(h·ft²) | 94.638 W/m² |
| 40 BTU/(h·ft²) | 126.18 W/m² |
| 50 BTU/(h·ft²) | 157.73 W/m² |
| 75 BTU/(h·ft²) | 236.59 W/m² |
| 100 BTU/(h·ft²) | 315.46 W/m² |
| 250 BTU/(h·ft²) | 788.65 W/m² |
| 500 BTU/(h·ft²) | 1,577.3 W/m² |
| 1,000 BTU/(h·ft²) | 3,154.6 W/m² |
About these units
BTU per hour square foot (BTU/(h·ft²))
US & imperial (identical)
1 BTU/(h·ft²) ≈ 3.1545907 W/m²
BTU per hour per square foot, about 3.1546 W/m².
Source: NIST SP 811 / Handbook 44
Watt per square metre (W/m²)
SI (metric)
Base unit
The SI unit of heat flux (and irradiance). Solar irradiance at ground is about 1,000 W/m².
Source: BIPM SI Brochure (9th ed.)
Frequently asked questions
How do I convert BTU per hour square foot to watts per square metre?
Use W/m² = BTU/(h·ft²) × 3.154590745. Multiply the value in BTU per hour square foot by 3.154590745.
How many watts per square metre are in 1 BTU per hour square foot?
1 BTU per hour square foot (BTU/(h·ft²)) equals 3.1546 watts per square metre (W/m²); more precisely 3.154590745.
How many BTU per hour square foot are in 1 watt per square metre?
1 watt per square metre (W/m²) equals 0.317 BTU per hour square foot (BTU/(h·ft²)); more precisely 0.3169983306.
What is 10 BTU/(h·ft²) in W/m²?
10 BTU per hour square foot = 31.546 watts per square metre.
What is a BTU per hour square foot?
BTU per hour per square foot, about 3.1546 W/m².
What is a watt per square metre?
The SI unit of heat flux (and irradiance). Solar irradiance at ground is about 1,000 W/m².
Related conversions
Formula: W/m² = BTU/(h·ft²) × 3.154590745. Factors last reviewed 2026-10-27.