4 Foot-Pound to BTU (th)
Quick answer
4 Foot-Pound (ft·lbf) equals
0.005144 BTU
To convert 4 Foot-Pounds to BTU (th)s, multiply by 0.0012859278. Therefore, 4 Foot-Pound (ft·lbf) equals 0.005144 BTU (th) (BTU).
Formula: BTU = ft·lbf × 0.0012859278. Calculation: 4 × 0.0012859278 = 0.005144 BTU.
Convert Foot-Pound (ft·lbf) to BTU (th) (BTU) online with our free unit converter. In energy, 1 ft·lbf = 0.001286 BTU. Explore step-by-step conversion steps, mathematical formulas, and quick conversion reference tables below.
Worked example: converting Foot-Pound to BTU (th)
- Step 1 — start with the formula. BTU = ft·lbf × 0.0012859278
- Step 2 — substitute your figure. 4 ft·lbf × 0.0012859278
- Step 3 — read the result. 4 ft·lbf = 0.005144 BTU
- Step 4 — check it in reverse. ft·lbf = BTU × 777.6486521085 returns 4.0002 ft·lbf, which matches the figure you started with.
Energy Converter
27 units available
4 ft·lbf = 0.005144 BTU
Formula:
BTU = ft·lbf × 0.0012859278With your value: 4 ft·lbf = 0.00514371 BTU
How big is that?
Everyday references on a logarithmic scale, all expressed in foot-pound so you can sanity-check the result.
Other Foot-Pound to BTU (th) conversions
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
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
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
Foot-Pound and BTU (th) Relationship
Both Foot-Pound and BTU (th) belong to the US Customary / Imperial system, making this an intra-system conversion within energy. Since 1 Foot-Pound represents a fraction of a BTU (th) (1 BTU (th) ≈ 777.6487 Foot-Pounds), the BTU (th) is the larger measurement interval. Understanding the relationship between Foot-Pound and BTU (th) is essential for accurate calculations in physics, engineering, commerce, and daily applications.
About Foot-Pound
The Foot-Pound (symbol: ft·lbf) is a recognized unit in the US Customary / Imperial measurement framework, utilized within energy applications for precision and standardized data representation.
Common uses of Foot-Pound: energy calculations, engineering and science, education.
About BTU (th)
The BTU (th) (symbol: BTU) is a recognized unit in the US Customary / Imperial measurement framework, utilized within energy applications for precision and standardized data representation.
Common uses of BTU (th): energy calculations, engineering and science, education.
Frequently Asked Questions
- What is 4 Foot-Pound in BTU (th)?
- 4 Foot-Pound equals 0.005144 BTU (th).
- How many BTU (th)s are in 1 Foot-Pound?
- There are exactly 0.0012859278 BTU (th)s 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-Pounds to BTU (th)s, you would multiply 10 by 0.0012859278.
- What is a Foot-Pound?
- The Foot-Pound (symbol: ft·lbf) is a recognized unit in the US Customary / Imperial measurement framework, utilized within energy applications for precision and standardized data representation.
- What is a BTU (th)?
- The BTU (th) (symbol: BTU) is a recognized unit in the US Customary / Imperial measurement framework, utilized within energy applications for precision and standardized data representation.
- What are the common uses of Foot-Pound?
- The Foot-Pound is commonly used in energy calculations, engineering and science, education.
Related Energy Conversions
Cite this page
UnitConvertLab. (2026). 4 Foot-Pound to BTU (th). UnitConvertLab. Retrieved from https://unitconvertlab.com/convert/4-foot_pound-to-btu