Foot-Pound to BTU (th) Converter

Energy Converter

27 units available

Decimals:

From

To

0.001286

1 ft·lbf = 0.001286 BTU

Formula:

BTU = ft·lbf × 0.0012859278

With your value: 1 ft·lbf = 0.00128593 BTU

How big is that?

Everyday references on a logarithmic scale, all expressed in foot-pound so you can sanity-check the result.

Heartbeat (1/1.4 your value)0.738 ft·lbf

Your value1.00 ft·lbf

AA battery charge (7.4e+3× your value)7.38e+3 ft·lbf

Slice of bread (2.1e+5× your value)2.07e+5 ft·lbf

Daily food intake (6.2e+6× your value)6.20e+6 ft·lbf

Litre of petrol (2.5e+7× your value)2.52e+7 ft·lbf

Other Foot-Pound to BTU (th) conversions

2 ft·lbf to BTU 3 ft·lbf to BTU 4 ft·lbf to BTU 5 ft·lbf to BTU 6 ft·lbf to BTU 7 ft·lbf to BTU 8 ft·lbf to BTU

Foot-Pound to BTU (th) Conversion Table

Foot-Pound (ft·lbf)	BTU (th) (BTU)
0.5	0.000643
1	0.001286
2	0.002572
5	0.00643
10	0.012859
15	0.019289
20	0.025719
25	0.032148
50	0.064296
100	0.128593
250	0.321482
500	0.642964
1000	1.285928

BTU (th) to Foot-Pound Conversion Table

BTU (th) (BTU)	Foot-Pound (ft·lbf)
0.5	388.824326
1	777.648652
2	1,555.297304
5	3,888.243261
10	7,776.486521
15	11,664.729782
20	15,552.973042
25	19,441.216303
50	38,882.432605
100	77,764.865211
250	194,412.163027
500	388,824.326054
1000	777,648.652108

Where these values come from

Every factor on this page is traced to the document that defines it. See the full provenance dataset or our methodology.

Foot-Pound (ft·lbf)

Energy

Exact conversion

Derived from the joule (1 J = 1 kg·m²/s²). Thermochemical and IT calories, BTU and kWh are exact defined multiples.

Source: NIST Special Publication 811, Guide for the Use of the International System of Units

National Institute of Standards and Technology (US) · Reviewed 2026-07-01

BTU (th) (BTU)

Energy

Exact conversion

The International Table BTU is exactly 1055.055 852 62 J.

Thermochemical and 39 °F BTU definitions differ by up to 0.2 %.

Source: NIST Special Publication 811, Guide for the Use of the International System of Units

National Institute of Standards and Technology (US) · Reviewed 2026-07-01

How to Convert Foot-Pound to BTU (th)

To convert from Foot-Pound (ft·lbf) to BTU (th) (BTU), multiply the value by 0.0012859278.

Formula: BTU = ft·lbf × 0.0012859278

Reverse: ft·lbf = BTU × 777.6486521085

Step-by-Step Example

Start with your value in Foot-Pound. For example: 5 ft·lbf
Multiply by the conversion factor: 5 x 0.0012859278
The result is: 0.00643 BTU

About Foot-Pound

The foot-pound (ft·lbf) is a unit of energy and work. One foot-pound equals 1.355817948 joules. UnitConvertLab converts it against every other energy unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.

Common uses: energy calculations, engineering and science, education.

About BTU (th)

The btu (th) (BTU) is a unit of energy and work. One btu (th) equals 1054.35 joules. UnitConvertLab converts it against every other energy unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.

Common uses: energy calculations, engineering and science, education.

Frequently Asked Questions

How many BTU (th) are in 1 Foot-Pound?

There are exactly 0.0012859278 BTU (th) in 1 Foot-Pound. This means the conversion factor from Foot-Pound to BTU (th) is 0.0012859278.

What is the formula to convert Foot-Pound to BTU (th)?

The formula to convert Foot-Pound to BTU (th) is: BTU = ft·lbf × 0.0012859278. For example, to convert 10 Foot-Pound to BTU (th), you would multiply 10 by 0.0012859278.

What is a Foot-Pound?