Work from one pound-force over one foot.
Foot-pounds to Zettajoules Converter — ft-lb to ZJ
Convert Foot-pound (ft-lb) to Zettajoule (ZJ) using the exact conversion factor (1 foot-pound = 1.355818e-21 zettajoule). See the formula, worked examples, and conversion table.
Foot-pounds to Zettajoules converter
Converter
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Context values
Some unit families need one extra value for a physically accurate result.
Zettajoule is 1e+21 joule units.
Result = input x 1.355817948 / 1e+21.
Energy uses the joule as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Foot-pounds to Zettajoules
Foot-pound and Zettajoule 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 zettajoule is 1e+21 joule units.
Formula
zettajoules = 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 zettajoule equals 1e+21 base units, so dividing one by the other gives the direct foot-pound-to-zettajoule factor of 1.355818e-21.
Simple example
1 ft-lb × 1.355818e-21 = 1.355818e-21 ZJ
1 foot-pound = 1.355818e-21 zettajoules.
Real-world example
100 ft-lb × 1.355818e-21 = 1.355818e-19 ZJ
100 foot-pounds = 1.355818e-19 zettajoules.
Conversion table
| Foot-pound (ft-lb) | Zettajoule (ZJ) |
|---|---|
| 1 ft-lb | 1.355818e-21 ZJ |
| 10 ft-lb | 1.355818e-20 ZJ |
| 100 ft-lb | 1.355818e-19 ZJ |
| 500 ft-lb | 6.77909e-19 ZJ |
| 1,000 ft-lb | 1.355818e-18 ZJ |
| 2,000 ft-lb | 2.711636e-18 ZJ |
Reverse conversion: Zettajoule to Foot-pound
1.355818e-21 ZJ × 7.375621e+20 = 1.000000038 ft-lb
1.355818e-21 zettajoules = 1.000000038 foot-pounds.
foot-pounds = zettajoules × 7.375621e+20
For a page dedicated to this direction, see Zettajoule to Foot-pound.
Understanding the Foot-pound (ft-lb)
Work from one pound-force over one foot.
Understanding the Zettajoule (ZJ)
Zettajoule is 1e+21 joule units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many zettajoules are in 1 foot-pound?
1 foot-pound equals 1.355818e-21 zettajoules, using the exact defined conversion factor rather than an estimate.
How do I convert foot-pound to zettajoule?
Multiply the foot-pound value by 1.355818e-21. The converter above does this instantly to whatever precision you set.
How do I convert zettajoule back to foot-pound?
Use the reverse factor: 1 zettajoule equals 7.375621e+20 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 zettajoule?
Zettajoule (ZJ) is a unit of energy.
Is the foot-pound to zettajoule conversion exact?
Yes. Both foot-pound and zettajoule 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.