Work from one pound-force over one foot.
Foot-pounds to Femtojoules Converter — ft-lb to fJ
Convert Foot-pound (ft-lb) to Femtojoule (fJ) using the exact conversion factor (1 foot-pound = 1.355818e+15 femtojoule). See the formula, worked examples, and conversion table.
Foot-pounds to Femtojoules converter
Converter
Energy Converter
Convert joules, calories, kilowatt-hours, BTU, electronvolts, therms, and mechanical work units.
Context values
Some unit families need one extra value for a physically accurate result.
Femtojoule is 1e-15 joule units.
Result = input x 1.355817948 / 1e-15.
Energy uses the joule as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Foot-pounds to Femtojoules
Foot-pound and Femtojoule both measure energy, and the conversion is especially useful for comparing nutrition labels (kilocalories) against scientific energy figures (joules). Specifically: Work from one pound-force over one foot, and femtojoule is 1e-15 joule units.
Formula
femtojoules = foot-pounds × 1.355818e+15
This factor comes from each unit's defined relationship to the category's base unit: 1 foot-pound equals 1.35581794833 base units, and 1 femtojoule equals 1e-15 base units, so dividing one by the other gives the direct foot-pound-to-femtojoule factor of 1.355818e+15.
Simple example
1 ft-lb × 1.355818e+15 = 1.355818e+15 fJ
1 foot-pound = 1.355818e+15 femtojoules.
Real-world example
100 ft-lb × 1.355818e+15 = 1.355818e+17 fJ
100 foot-pounds = 1.355818e+17 femtojoules.
Conversion table
| Foot-pound (ft-lb) | Femtojoule (fJ) |
|---|---|
| 1 ft-lb | 1.355818e+15 fJ |
| 10 ft-lb | 1.355818e+16 fJ |
| 100 ft-lb | 1.355818e+17 fJ |
| 500 ft-lb | 6.77909e+17 fJ |
| 1,000 ft-lb | 1.355818e+18 fJ |
| 2,000 ft-lb | 2.711636e+18 fJ |
Reverse conversion: Femtojoule to Foot-pound
1.355818e+15 fJ × 7.375621e-16 = 1.000000038 ft-lb
1.355818e+15 femtojoules = 1.000000038 foot-pounds.
foot-pounds = femtojoules × 7.375621e-16
For a page dedicated to this direction, see Femtojoule to Foot-pound.
Understanding the Foot-pound (ft-lb)
Work from one pound-force over one foot.
Understanding the Femtojoule (fJ)
Femtojoule is 1e-15 joule units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many femtojoules are in 1 foot-pound?
1 foot-pound equals 1.355818e+15 femtojoules, using the exact defined conversion factor rather than an estimate.
How do I convert foot-pound to femtojoule?
Multiply the foot-pound value by 1.355818e+15. The converter above does this instantly to whatever precision you set.
How do I convert femtojoule back to foot-pound?
Use the reverse factor: 1 femtojoule equals 7.375621e-16 foot-pounds. You can also use the swap control in the converter above to flip the direction instantly.
What is a foot-pound?
Foot-pound (ft-lb) is a unit of energy.
What is a femtojoule?
Femtojoule (fJ) is a unit of energy.
Is the foot-pound to femtojoule conversion exact?
Yes. Both foot-pound and femtojoule are defined by fixed standards rather than physical artifacts, so the factor of 1.355818e+15 used above is exact to as many digits as you choose to display.