Convert Joules per Kilogram to Foot-Pounds per Pound
Instantly convert Joules per Kilogram (J/kg) to Foot-Pounds per Pound (ft·lbf/lb) with our free online calculator.
Formula: J/kg to ft·lbf/lb — multiply by 0.334552
Reference Table
| Joules per Kilogram (J/kg) | Foot-Pounds per Pound (ft·lbf/lb) |
|---|---|
| 1 | 0.334552 |
| 5 | 1.67276 |
| 10 | 3.34552 |
| 25 | 8.36381 |
| 50 | 16.7276 |
| 100 | 33.4552 |
How to Convert Joules per Kilogram to Foot-Pounds per Pound
Formula
To convert Joules per Kilogram (J/kg) to Foot-Pounds per Pound (ft·lbf/lb): multiply by 0.334552
Step-by-Step
- Start with your value in Joules per Kilogram (J/kg).
- Multiply by 0.334552 to perform the conversion.
- The result is your value expressed in Foot-Pounds per Pound (ft·lbf/lb).
Conversion Factor
1 J/kg = 0.334552 ft·lbf/lb
Reverse Factor
1 ft·lbf/lb = 2.98907 J/kg
Worked Example
Convert 25 Joules per Kilogram to Foot-Pounds per Pound: 25 J/kg = 8.36381 ft·lbf/lb
About Joule per Kilogram (J/kg)
The SI unit of specific energy (energy per unit mass) per ISO 80000-5 §5-15 — used for gravimetric energy density of fuels, batteries, explosives, and propellants. J/kg is the universal unit for cross-technology energy-storage comparisons, and the natural unit for kinetic-energy-per-mass (E_k/m = ½v² in J/kg = m²/s²). Reference values for energy-storage media per Sandia National Labs / DOE battery testing protocols and NFPA 921 fire-investigation reference data: lithium-ion 18650 cell ~550,000 J/kg (gravimetric); lithium-iron-phosphate (LFP, LiFePO₄) cells 360,000-450,000 J/kg; lead-acid battery 110,000-180,000 J/kg; gasoline 46,400,000 J/kg lower heating value (LHV) per ASTM D4868; diesel 45,500,000 J/kg LHV; coal (bituminous) ~24,000,000 J/kg; TNT 4,184,000 J/kg (the explosive-yield reference standard, basis of 'megaton' nuclear yield); hydrogen H₂ gas 120,000,000 J/kg LHV (highest gravimetric of any chemical fuel); jet fuel Jet-A 43,150,000 J/kg per ASTM D1655. Specific energy is also the key metric for compressed-air storage (CAES), pumped-hydro per-mass equivalent (gh = 9.81·h J/kg), and projectile kinetic energy per unit mass.
About Foot-Pound per Pound (ft·lbf/lb)
An imperial specific-energy unit equal to approximately 2.98907 J/kg (1 ft·lbf = 1.35582 J; 1 lb = 0.45359237 kg; ratio = 2.98907). ft·lbf/lb is a niche US-engineering unit used primarily in: ballistic kinetic-energy-per-mass calculations (E_k/m for projectiles, where US ballistics literature historically uses imperial mass for the projectile and ft·lbf for muzzle energy — a .308 Winchester 168gr bullet at 2,650 fps muzzle velocity has specific energy ~109,000 ft·lbf/lb), US-edition mechanical-engineering textbooks for mechanical strain-energy-per-mass calculations (Shigley, Norton, Hibbeler in dual-unit editions), and head-loss / hydraulic-energy specific calculations in US civil-engineering hydraulics where the natural unit is feet-of-head (1 ft of head of water ≈ 1 ft·lbf/lb specific gravitational potential). For typical engineering specific-energy scales (gasoline, batteries, structural-strain energy), the ft·lbf/lb numerical value is large and unwieldy — gasoline LHV is ~15.5 million ft·lbf/lb — so US engineers usually convert to BTU/lb for fuel work and reserve ft·lbf/lb for kinetic and elastic-strain applications. Convert ft·lbf/lb to J/kg by multiplying by 2.98907.
Quick Facts
- 1 Joule per Kilogram equals 0.334552 Foot-Pounds per Pound
- 1 Foot-Pound per Pound equals 2.98907 Joules per Kilogram
- Joule per Kilogram is a unit of specific energy
- Foot-Pound per Pound is a unit of specific energy
- This conversion is commonly used in fuel comparison, battery technology, and rocket propulsion
- The Joule per Kilogram belongs to the metric system
- The Foot-Pound per Pound belongs to the imperial system
Common Joule per Kilogram to Foot-Pound per Pound Conversions
| Joules per Kilogram (J/kg) | Foot-Pounds per Pound (ft·lbf/lb) |
|---|---|
| 0.01 | 0.00334552 |
| 0.1 | 0.0334552 |
| 0.25 | 0.0836381 |
| 0.5 | 0.167276 |
| 1 | 0.334552 |
| 2 | 0.669104 |
| 3 | 1.00366 |
| 5 | 1.67276 |
| 10 | 3.34552 |
| 15 | 5.01828 |
| 20 | 6.69104 |
| 25 | 8.36381 |
| 50 | 16.7276 |
| 75 | 25.0914 |
| 100 | 33.4552 |
| 250 | 83.6381 |
| 500 | 167.276 |
| 1000 | 334.552 |
| 5000 | 1672.76 |
| 10000 | 3345.52 |
Understanding Joules per Kilogram
The Joule per Kilogram (symbol: J/kg) is a unit of specific energy. The SI unit of specific energy (energy per unit mass) per ISO 80000-5 §5-15 — used for gravimetric energy density of fuels, batteries, explosives, and propellants. J/kg is the universal unit for cross-technology energy-storage comparisons, and the natural unit for kinetic-energy-per-mass (E_k/m = ½v² in J/kg = m²/s²). Reference values for energy-storage media per Sandia National Labs / DOE battery testing protocols and NFPA 921 fire-investigation reference data: lithium-ion 18650 cell ~550,000 J/kg (gravimetric); lithium-iron-phosphate (LFP, LiFePO₄) cells 360,000-450,000 J/kg; lead-acid battery 110,000-180,000 J/kg; gasoline 46,400,000 J/kg lower heating value (LHV) per ASTM D4868; diesel 45,500,000 J/kg LHV; coal (bituminous) ~24,000,000 J/kg; TNT 4,184,000 J/kg (the explosive-yield reference standard, basis of 'megaton' nuclear yield); hydrogen H₂ gas 120,000,000 J/kg LHV (highest gravimetric of any chemical fuel); jet fuel Jet-A 43,150,000 J/kg per ASTM D1655. Specific energy is also the key metric for compressed-air storage (CAES), pumped-hydro per-mass equivalent (gh = 9.81·h J/kg), and projectile kinetic energy per unit mass.
It belongs to the metric measurement system.
Joules per Kilogram are commonly used in fuel comparison, battery technology, and rocket propulsion.
Understanding Foot-Pounds per Pound
The Foot-Pound per Pound (symbol: ft·lbf/lb) is a unit of specific energy. An imperial specific-energy unit equal to approximately 2.98907 J/kg (1 ft·lbf = 1.35582 J; 1 lb = 0.45359237 kg; ratio = 2.98907). ft·lbf/lb is a niche US-engineering unit used primarily in: ballistic kinetic-energy-per-mass calculations (E_k/m for projectiles, where US ballistics literature historically uses imperial mass for the projectile and ft·lbf for muzzle energy — a .308 Winchester 168gr bullet at 2,650 fps muzzle velocity has specific energy ~109,000 ft·lbf/lb), US-edition mechanical-engineering textbooks for mechanical strain-energy-per-mass calculations (Shigley, Norton, Hibbeler in dual-unit editions), and head-loss / hydraulic-energy specific calculations in US civil-engineering hydraulics where the natural unit is feet-of-head (1 ft of head of water ≈ 1 ft·lbf/lb specific gravitational potential). For typical engineering specific-energy scales (gasoline, batteries, structural-strain energy), the ft·lbf/lb numerical value is large and unwieldy — gasoline LHV is ~15.5 million ft·lbf/lb — so US engineers usually convert to BTU/lb for fuel work and reserve ft·lbf/lb for kinetic and elastic-strain applications. Convert ft·lbf/lb to J/kg by multiplying by 2.98907.
It belongs to the imperial measurement system.
Foot-Pounds per Pound are commonly used in fuel comparison, battery technology, and rocket propulsion.
Why Convert Joules per Kilogram to Foot-Pounds per Pound?
Converting between Joules per Kilogram and Foot-Pounds per Pound is a frequent requirement for engineers, scientists, and students working with specific energy values. Different industries and regions favour different unit systems, so having a dependable conversion tool saves time and prevents errors in technical calculations. Whether you are verifying a specification sheet, cross-checking simulation results, or preparing a report for an international audience, accurate specific energy conversion is essential.
Frequently Asked Questions
How do I convert Joules per Kilogram to Foot-Pounds per Pound?
The SI unit of specific energy (energy per unit mass) per ISO 80000-5 §5-15 — used for gravimetric energy density of fuels, batteries, explosives, and propellants. To convert Joules per Kilogram to Foot-Pounds per Pound, multiply by 0.334552. For example, 25 J/kg equals 8.36381 ft·lbf/lb.
How many Foot-Pounds per Pound are in 1 Joule per Kilogram?
There are 0.334552 Foot-Pounds per Pound in 1 Joule per Kilogram.
How many Joules per Kilogram are in 1 Foot-Pound per Pound?
There are 2.98907 Joules per Kilogram in 1 Foot-Pound per Pound.
What is the formula for Joule per Kilogram to Foot-Pound per Pound conversion?
The formula is: multiply by 0.334552. This means 1 J/kg = 0.334552 ft·lbf/lb.
Is a Joule per Kilogram bigger than a Foot-Pound per Pound?
Yes. One Joule per Kilogram is larger than one Foot-Pound per Pound because 1 J/kg equals 0.334552 ft·lbf/lb, which is less than 1.
When do you need to convert between Joules per Kilogram and Foot-Pounds per Pound?
An imperial specific-energy unit equal to approximately 2. Joule per Kilogram and Foot-Pound per Pound are both specific energy units, so conversion comes up whenever one source of information uses one unit and another uses the other — a classic cross-reference challenge in engineering, trade, travel, and everyday life.