How many foot-pounds is 1 BTU?

1 BTU (IT) equals 778.16926 foot-pounds-force (ft·lbf). This relationship comes from the mechanical equivalent of heat: 1 BTU = 1055.05585 J, and 1 ft·lbf = 1.35582 J, giving 1055.05585 / 1.35582 ≈ 778.169 ft·lbf.

How do I convert BTU to foot-pounds manually?

Multiply the BTU value by 778.16926. For example, 5 BTU × 778.16926 = 3890.85 ft·lbf. To convert foot-pounds back to BTU, divide by 778.16926 (or multiply by approximately 0.001285).

What is the difference between BTU and foot-pound?

Both measure energy, but from different origins. The BTU (British Thermal Unit) is a thermal unit — the energy needed to raise one pound of water by 1 °F. The foot-pound (ft·lbf) is a mechanical unit — the work done by a force of one pound-force over one foot of displacement. They are related through the mechanical equivalent of heat.

What is the mechanical equivalent of heat?

The mechanical equivalent of heat is the relationship between thermal energy (heat) and mechanical work. James Prescott Joule established that 1 BTU ≈ 778 ft·lbf in the 19th century. This equivalence is fundamental to thermodynamics and forms the basis of the first law of thermodynamics.

When would I need to convert BTU to foot-pounds?

This conversion is useful in mechanical engineering, ballistics, and steam/combustion engine analysis where energy may be specified in thermal units (BTU) but needs to be compared to mechanical work (ft·lbf). It also appears in physics problems involving thermodynamic cycles.

Is foot-pound the same as foot-pound-force?

Yes. Foot-pound (ft·lbf) is shorthand for foot-pound-force, a unit of energy or work. Do not confuse it with pound-foot (lb·ft), which is a unit of torque — though the numbers happen to be equal in magnitude, they represent different physical quantities.

BTU to Foot Pounds Converter

Name: BTU to Foot Pounds Converter
Availability: InStock
Author: Nham Vu

Enter a value in BTU and get the foot-pound equivalent instantly, with reverse foot-pound-to-BTU conversion and a reference table.

Converter

Energy in BTU (British Thermal Units)

= 778.16926 ft·lbf

Energy in Foot-Pounds (ft·lbf)

= 1 BTU

Reference Table

BTU	ft·lbf
0.001	0.77817
0.01	7.7817
0.1	77.817
1	778.169
5	3,890.85
10	7,781.69
50	38,908.5
100	77,816.9
500	389,085
1,000	778,169

1 BTU (IT) = 778.16926 ft·lbf. Based on 1 BTU = 1055.05585 J and 1 ft·lbf = 1.35582 J.

Summary

Enter a value in BTU and get the foot-pound equivalent instantly, with reverse foot-pound-to-BTU conversion and a reference table.

How it works

Enter an energy value in BTU in the top input field.
The foot-pound result appears instantly — no button press needed.
Use the reverse field to convert foot-pounds back to BTU.
Click "Copy" next to any result to copy the value to your clipboard.
Check the reference table for common BTU-to-foot-pound values at a glance.

Use cases

Convert furnace or boiler output from BTU to foot-pounds for mechanical energy comparisons.
Translate engine torque specifications when mixing imperial thermal and mechanical units.
Cross-check firearm or ballistic energy ratings given in BTU against ft·lbf impact values.
Convert heat energy in thermodynamic calculations from BTU to the mechanical equivalent.
Compare HVAC system energy consumption in BTU to mechanical work in foot-pounds.
Verify refrigeration cycle energy balances that involve both thermal and mechanical units.
Convert natural gas energy content from BTU to foot-pounds for combustion engine analysis.
Cross-reference historical steam engine efficiency data that mixes BTU and ft·lbf figures.

Frequently Asked Questions

Last updated: 2026-07-22 · Reviewed by Nham Vu