Work from one pound-force over one foot.
Foot-pounds to Zeptojoules Converter — ft-lb to zJ
Convert Foot-pound (ft-lb) to Zeptojoule (zJ) using the exact conversion factor (1 foot-pound = 1.355818e+21 zeptojoule). See the formula, worked examples, and conversion table.
Foot-pounds to Zeptojoules converter
Converter
Engineering Converter
Convert common stress, force, torque, power, and energy units used in engineering.
Context values
Some unit families need one extra value for a physically accurate result.
Zeptojoule is 1e-21 joule units.
Result = input x 1.355817948 / 1e-21.
Energy units are compatible.
Reserved above the conversion cards and below the converter.
About Converting Foot-pounds to Zeptojoules
Foot-pound and Zeptojoule both measure a quantity used in structural or mechanical engineering — commonly stress, pressure, force, torque, power, or energy — where converting between the unit conventions used in different regions, industries, or equipment specifications is a routine part of design work. Specifically: Work from one pound-force over one foot, and zeptojoule is 1e-21 joule units.
Formula
zeptojoules = foot-pounds × 1.355818e+21
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 zeptojoule equals 1e-21 base units, so dividing one by the other gives the direct foot-pound-to-zeptojoule factor of 1.355818e+21.
Simple example
1 ft-lb × 1.355818e+21 = 1.355818e+21 zJ
1 foot-pound = 1.355818e+21 zeptojoules.
Real-world example
100 ft-lb × 1.355818e+21 = 1.355818e+23 zJ
100 foot-pounds = 1.355818e+23 zeptojoules.
Conversion table
| Foot-pound (ft-lb) | Zeptojoule (zJ) |
|---|---|
| 1 ft-lb | 1.355818e+21 zJ |
| 10 ft-lb | 1.355818e+22 zJ |
| 50 ft-lb | 6.77909e+22 zJ |
| 100 ft-lb | 1.355818e+23 zJ |
| 500 ft-lb | 6.77909e+23 zJ |
| 1,000 ft-lb | 1.355818e+24 zJ |
Reverse conversion: Zeptojoule to Foot-pound
1.355818e+21 zJ × 7.375621e-22 = 1.000000038 ft-lb
1.355818e+21 zeptojoules = 1.000000038 foot-pounds.
foot-pounds = zeptojoules × 7.375621e-22
For a page dedicated to this direction, see Zeptojoule to Foot-pound.
Understanding the Foot-pound (ft-lb)
Work from one pound-force over one foot.
Understanding the Zeptojoule (zJ)
Zeptojoule is 1e-21 joule units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many zeptojoules are in 1 foot-pound?
1 foot-pound equals 1.355818e+21 zeptojoules, using the exact defined conversion factor rather than an estimate.
How do I convert foot-pound to zeptojoule?
Multiply the foot-pound value by 1.355818e+21. The converter above does this instantly to whatever precision you set.
How do I convert zeptojoule back to foot-pound?
Use the reverse factor: 1 zeptojoule equals 7.375621e-22 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 engineering.
What is a zeptojoule?
Zeptojoule (zJ) is a unit of engineering.
Is the foot-pound to zeptojoule conversion exact?
Yes. Both foot-pound and zeptojoule are defined by fixed standards rather than physical artifacts, so the factor of 1.355818e+21 used above is exact to as many digits as you choose to display.
Why do engineering unit conventions vary so much by region and industry?
Pressure, force, and stress can be expressed in metric (pascal, newton), US customary (psi, pound-force), or older and industry-specific units (atmosphere, torr, kip) depending on the country, industry, and even the equipment manufacturer, which is why engineers routinely need to convert between them when working across specs from different sources.