Btu to Fahrenheit Converter
Heat added to a material lifts its temperature. Divide the Btu by the mass and the specific heat.
Quick answer: Divide the Btu by the mass in pounds times the specific heat in Btu per pound per °F. For example, 5,000 Btu into 100 lb with specific heat 1 is 50 °F, 10,000 Btu into 50 lb with specific heat 0.5 is 400 °F and 2,000 Btu into 20 lb with specific heat 0.2 is 500 °F.
The Btu to Fahrenheit formula
Heat added equals mass times specific heat times the temperature change (Wikipedia: Specific heat capacity).
So the rise in °F equals the Btu divided by the pounds times the specific heat.
Take 5,000 Btu into 100 lb with specific heat 1. 5,000 ÷ (100 × 1) gives 50 °F.
Take 10,000 Btu into 50 lb with specific heat 0.5. 10,000 ÷ (50 × 0.5) gives 400 °F.
Btu to Fahrenheit step by step
Enter the heat added in Btu.
Enter the mass in pounds.
Enter the specific heat in Btu per pound per °F.
°F is the result. The last column gives °C.
How to convert Btu to Fahrenheit step by step
- Enter the heat added in Btu.
- Enter the mass in pounds.
- Enter the specific heat in Btu per pound per °F.
- Read the result in °F.
- Check it against the quick table.
Example 1: 5,000 Btu into 100 lb with specific heat 1
- Start with 5,000 Btu into 100 lb with specific heat 1.
- 5,000 ÷ (100 × 1) = 50.
- The result is 50 °F.
5,000 Btu into 100 lb with specific heat 1 = 50 °F
Example 2: 10,000 Btu into 50 lb with specific heat 0.5
- Start with 10,000 Btu into 50 lb with specific heat 0.5.
- 10,000 ÷ (50 × 0.5) = 400.
- The result is 400 °F.
10,000 Btu into 50 lb with specific heat 0.5 = 400 °F
Example 3: 2,000 Btu into 20 lb with specific heat 0.2
- Start with 2,000 Btu into 20 lb with specific heat 0.2.
- 2,000 ÷ (20 × 0.2) = 500.
- The result is 500 °F.
2,000 Btu into 20 lb with specific heat 0.2 = 500 °F
The sum assumes no heat is lost and the specific heat stays the same over the range.
Btu to Fahrenheit conversion table
| Heat, mass, specific heat | °F | °C |
|---|---|---|
| 5,000 Btu into 100 lb with specific heat 1 | 50 °F | 27.778 °C |
| 1,000 Btu into 100 lb with specific heat 1 | 10 °F | 5.556 °C |
| 10,000 Btu into 50 lb with specific heat 0.5 | 400 °F | 222.22 °C |
| 2,000 Btu into 20 lb with specific heat 0.2 | 500 °F | 277.78 °C |
| 8,000 Btu into 200 lb with specific heat 1 | 40 °F | 22.222 °C |
| 500 Btu into 10 lb with specific heat 1 | 50 °F | 27.778 °C |
| 3,000 Btu into 40 lb with specific heat 0.25 | 300 °F | 166.67 °C |
| 20,000 Btu into 500 lb with specific heat 0.12 | 333.33 °F | 185.19 °C |
The highlighted row is the default of the calculator. The last column gives °C.
A quick mental shortcut for Btu to Fahrenheit
For water, divide the Btu by the pounds.
So 5,000 Btu in 100 lb of water raises it 50 °F.
What specific heat means
Specific heat is the heat needed to raise 1 pound by 1 °F.
The average value for water is 1 Btu per pound per °F (Wikipedia: Specific heat capacity).
Other materials
Most solids and gases need less heat than water for the same rise.
Iron, for example, has about one ninth of the specific heat of water by weight (Wikipedia: Specific heat capacity).
Worked example: 5,000 Btu into 100 lb with specific heat 1
5,000 Btu into 100 lb with specific heat 1 gives 50 °F.
The same inputs give 27.778 °C in the last column.
Worked example: 10,000 Btu into 50 lb with specific heat 0.5
10,000 Btu into 50 lb with specific heat 0.5 gives 400 °F.
The same inputs give 222.22 °C in the last column.
Worked example: 2,000 Btu into 20 lb with specific heat 0.2
2,000 Btu into 20 lb with specific heat 0.2 gives 500 °F.
The same inputs give 277.78 °C in the last column.
Heating water
Add 5,000 Btu to 100 lb of water.
It rises 50 °F, which is 27.778 °C.
Heating a lighter material
Add 10,000 Btu to 50 lb of a material with specific heat 0.5.
It rises 400 °F.
Going the other way
To go back, multiply the rise by the pounds and the specific heat.
So 50 °F for 5,000 Btu into 100 lb with specific heat 1 goes back to 5,000 Btu.
Check your answer
Reverse the answer with the back formula.
You should land on 5,000 Btu for 5,000 Btu into 100 lb with specific heat 1.
Quick conversion answers
| Conversion | Result |
|---|---|
| 1,000 Btu into 100 lb with specific heat 1 | 10 °F |
| 10,000 Btu into 50 lb with specific heat 0.5 | 400 °F |
| 2,000 Btu into 20 lb with specific heat 0.2 | 500 °F |
| 8,000 Btu into 200 lb with specific heat 1 | 40 °F |
| 500 Btu into 10 lb with specific heat 1 | 50 °F |
| 3,000 Btu into 40 lb with specific heat 0.25 | 300 °F |
Where this conversion is used
Heating and plumbing staff size heaters.
Students practise heat sums.
Engineers estimate warm-up times.
Common mistakes to avoid
- Using the wrong specific heat. Water is 1, but other materials differ.
- Mixing °F and °C. A rise of 1.8 °F is a rise of 1 °C.
- Forgetting the specific heat. 5,000 Btu into 100 lb raises the temperature 50 °F at a specific heat of 1, but 100 °F at 0.5.
- Using the wrong units. Check each input against the label on the page.
Related converters
Example: 10,000 Btu into 50 lb with specific heat 0.5
10,000 Btu into 50 lb with specific heat 0.5 gives 400 °F.
The same inputs give 222.22 °C in the last column.
Example: 2,000 Btu into 20 lb with specific heat 0.2
2,000 Btu into 20 lb with specific heat 0.2 gives 500 °F.
The same inputs give 277.78 °C in the last column.
Frequently asked questions
How do I find °F?
rise in °F = Btu ÷ (pounds × specific heat).
What is the answer for 5,000 Btu into 100 lb with specific heat 1?
50 °F.
What is the answer for 10,000 Btu into 50 lb with specific heat 0.5?
400 °F.
What is the specific heat of water?
About 1 Btu per pound per °F.
Does it change at a phase change?
Yes. Melting and boiling need extra heat with no rise in temperature.
How do I get °C?
Divide the °F rise by 1.8.
Sources
- Wikipedia: Specific heat capacity (en.wikipedia.org)
- Wikipedia: British thermal unit (en.wikipedia.org)
