Joule to Foot-pound Converter
Enter the value that you want to convert joule (J) to foot-pound (ft*lbf) or foot-pound to joule.
1 joule = 0.7375621 foot-pound
Formula: foot-pound = joule value × 0.7375621
J to FT*LBF — joule to foot-pound
10 joule = 7.37562 foot-pound
Popular Energy Converters:
Converting Joule to Foot-pound
The Joule in Engineering
Joule (J) is a unit of energy measurement. 1 joule is equal to 0.7375621 foot-pound.
What is Foot-pound?
Foot-pound (ft*lbf) is a unit of energy measurement. 1 foot-pound is equal to 1.3558179 joule.
Energy Units in Different Fields
Energy measurement units reflect their historical origins across different industries. Electrical engineers use kilowatt-hours, nutritionists use calories, physicists use joules, heating engineers use BTUs, and the petroleum industry uses barrels of oil equivalent. Converting between these units is essential for energy auditing, comparing fuel sources, sizing HVAC systems, and understanding electricity bills relative to gas consumption.
joule to foot-pound metric conversion table
| 0.01 J | = | 0.00738 ft*lbf |
| 0.1 J | = | 0.07376 ft*lbf |
| 1 J | = | 0.73756 ft*lbf |
| 2 J | = | 1.47512 ft*lbf |
| 3 J | = | 2.21269 ft*lbf |
| 4 J | = | 2.95025 ft*lbf |
| 5 J | = | 3.68781 ft*lbf |
| 6 J | = | 4.42537 ft*lbf |
| 7 J | = | 5.16294 ft*lbf |
| 8 J | = | 5.90050 ft*lbf |
| 9 J | = | 6.63806 ft*lbf |
| 10 J | = | 7.37562 ft*lbf |
| 11 J | = | 8.11318 ft*lbf |
| 12 J | = | 8.85075 ft*lbf |
| 13 J | = | 9.58831 ft*lbf |
| 14 J | = | 10.32587 ft*lbf |
| 15 J | = | 11.06343 ft*lbf |
| 16 J | = | 11.80099 ft*lbf |
| 17 J | = | 12.53856 ft*lbf |
| 18 J | = | 13.27612 ft*lbf |
| 19 J | = | 14.01368 ft*lbf |
| 20 J | = | 14.75124 ft*lbf |
| 30 J | = | 22.12686 ft*lbf |
| 40 J | = | 29.50249 ft*lbf |
| 50 J | = | 36.87811 ft*lbf |
| 60 J | = | 44.25373 ft*lbf |
| 70 J | = | 51.62935 ft*lbf |
| 80 J | = | 59.00497 ft*lbf |
| 90 J | = | 66.38059 ft*lbf |
| 100 J | = | 73.75621 ft*lbf |
| 200 J | = | 147.51243 ft*lbf |
| 300 J | = | 221.26864 ft*lbf |
| 400 J | = | 295.02486 ft*lbf |
| 500 J | = | 368.78107 ft*lbf |
| 600 J | = | 442.53729 ft*lbf |
| 700 J | = | 516.29350 ft*lbf |
| 800 J | = | 590.04972 ft*lbf |
| 900 J | = | 663.80593 ft*lbf |
| 1000 J | = | 737.56215 ft*lbf |
How to Convert J to FT*LBF (Joule to Foot-pound)?
We can convert joule to foot-pound by using an example.
Example:
Convert 20 Joule to Foot-pound?
We know 1 Joule = 0.7375621 foot-pound; 1 Foot-pound = 1.3558179 joule.
20 joule = ___ft*lbf
20 × 0.7375621 = 14.75124 ft*lbf (we know 1 joule = 0.7375621 foot-pound)
Answer:
20 joule = 14.75124 foot-pound
How to Convert Joules to Foot-Pounds (Step-by-Step)
Converting joules to foot-pounds is needed when translating SI energy or work measurements to US customary units used in mechanical engineering, ballistics, and impact testing. The conversion factor is 1 J = 0.737562 ft-lb.
- Identify the energy or work value in joules (J).
- Multiply by 0.737562 to convert to foot-pounds (ft-lb).
- Round to appropriate precision for the application.
- Verify the result makes sense in context (mechanical work, impact energy, etc.).
Common Joules to Foot-Pounds Conversions
Energy and work conversions for mechanical engineering, impact testing, and ballistics.
| Joule | Foot-pound |
|---|---|
| 1 J | 0.738 ft-lb |
| 1.356 J | 1 ft-lb |
| 10 J | 7.38 ft-lb |
| 50 J | 36.9 ft-lb |
| 100 J | 73.8 ft-lb |
| 500 J | 368.8 ft-lb |
| 1000 J | 737.6 ft-lb |
| 3500 J | 2581 ft-lb |
Solved Examples: Joules to Foot-Pounds Conversion
Question 1: A Charpy impact test yields 27 J for a steel specimen. Express in ft-lb.
Solution:
Start with 27 J.
Multiply by 0.737562: 27 × 0.737562 = 19.9 ft-lb.
This indicates moderate toughness for structural steel.
Answer: 27 J ≈ 19.9 ft-lb
Question 2: A projectile has 3200 J of kinetic energy at the muzzle. Convert to ft-lb.
Solution:
Start with 3200 J.
Multiply by 0.737562: 3200 × 0.737562 = 2360 ft-lb.
This is typical of a .30-06 rifle round.
Answer: 3200 J ≈ 2360 ft-lb
Question 3: A pendulum impact tester delivers 300 J. What is this in ft-lb?
Solution:
Start with 300 J.
Multiply by 0.737562: 300 × 0.737562 = 221.3 ft-lb.
This is the standard Charpy machine capacity (300 J / 221 ft-lb).
Answer: 300 J ≈ 221 ft-lb
Question 4: Work done by a force: F × d = 450 N × 2 m = 900 J. Convert to ft-lb.
Solution:
Work = 900 J.
Multiply by 0.737562: 900 × 0.737562 = 663.8 ft-lb.
Equivalent to lifting 663.8 lb by 1 foot (or 66.4 lb by 10 feet).
Answer: 900 J ≈ 664 ft-lb
Practice: Joules to Foot-Pounds Conversions
Try solving these on your own to test your understanding:
- Convert 15 J to ft-lb. (Answer: ≈ 11.1 ft-lb)
- A spring stores 80 J. Express in ft-lb. (Answer: ≈ 59.0 ft-lb)
- Convert 2000 J to ft-lb. (Answer: ≈ 1475 ft-lb)
- An impact test reads 45 J. Express in ft-lb. (Answer: ≈ 33.2 ft-lb)
- Convert 5 J to ft-lb. (Answer: ≈ 3.69 ft-lb)
Charpy and Izod Impact Testing
Material toughness is measured by breaking a notched specimen with a pendulum. The Charpy test (ISO 148) reports absorbed energy in joules. US ASTM standards historically used ft-lb. A minimum of 20 J (14.8 ft-lb) at -20°C is typical for structural steel. Offshore oil platforms may require 40 J (29.5 ft-lb) at -40°C. Converting between units is routine when comparing international material certifications.
Muzzle Energy and Ballistics
Firearms ballistics uses foot-pounds (ft-lb) in the US and joules internationally. A .22 LR produces about 140 J (103 ft-lb), a 9mm pistol about 500–600 J (370–440 ft-lb), and a .308 Winchester about 3500 J (2580 ft-lb). Hunting regulations in some jurisdictions specify minimum muzzle energy in joules or ft-lb for ethical harvesting of different game sizes.
Key Takeaways
- Multiply joules by 0.737562 to get foot-pounds.
- Quick estimate: J × 0.74 (or J × 3/4).
- 1 J ≈ 0.74 ft-lb; 1 ft-lb ≈ 1.356 J.
- Used in impact testing (Charpy/Izod), ballistics, and mechanical work.
- Standard Charpy test machine: 300 J = 221 ft-lb capacity.
- Context determines whether ft-lb means energy (work) or torque.
Joule to Foot-pound Conversion Formula
foot-pound = joule × 0.7375621
1 joule = 0.7375621 foot-pound
1 foot-pound = 1.3558179 joule
Reverse: joule = foot-pound × 1.3558179
Frequently Asked Questions
How many foot-pound are in 1 joule?
There are 0.7375621 foot-pound in 1 joule. To convert joule to foot-pound, multiply the value by 0.7375621.
How do I convert joule to foot-pound?
Multiply your joule value by 0.7375621 to get the equivalent in foot-pound. For example, 5 joule = 5 × 0.7375621 = 3.68781 foot-pound.
How do I convert foot-pound to joule?
Multiply your foot-pound value by 1.3558179 to get the equivalent in joule. Alternatively, divide by 0.7375621.
What is 10 joule in foot-pound?
10 joule is equal to 7.37562 foot-pound.
What is 100 joule in foot-pound?
100 joule is equal to 73.75621 foot-pound.