Torque from one pound-force at one foot.
Pound-feet to Zeptonewton meters Converter — lb ft to zN m
Convert Pound-foot (lb ft) to Zeptonewton meter (zN m) using the exact conversion factor (1 pound-foot = 1.355818e+21 zeptonewton meter). See the formula, worked examples, conversion table, history, and common uses.
Pound-feet to Zeptonewton meters converter
Converter
Torque Converter
Convert newton meters, pound-feet, pound-inches, ounce-inches, and kilogram-force meters.
Context values
Some unit families need one extra value for a physically accurate result.
Zeptonewton meter is 1e-21 newton meter units.
Result = input x 1.355817948 / 1e-21.
Torque uses the newton meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Pound-feet to Zeptonewton meters
Pound-foot and Zeptonewton meter both measure torque, and the conversion is essential for anyone using a torque wrench specified in one unit against a bolt or engine spec given in the other. Pound-foot is most often used for us torque wrench specifications (bolt tightening).
Formula
zeptonewton meters = pound-feet × 1.355818e+21
This factor comes from each unit's defined relationship to the category's base unit: 1 pound-foot equals 1.35581794833 base units, and 1 zeptonewton meter equals 1e-21 base units, so dividing one by the other gives the direct pound-foot-to-zeptonewton meter factor of 1.355818e+21.
Simple example
1 lb ft × 1.355818e+21 = 1.355818e+21 zN m
1 pound-foot = 1.355818e+21 zeptonewton meters.
Real-world example
10 lb ft × 1.355818e+21 = 1.355818e+22 zN m
10 pound-feet = 1.355818e+22 zeptonewton meters.
Conversion table
| Pound-foot (lb ft) | Zeptonewton meter (zN m) |
|---|---|
| 1 lb ft | 1.355818e+21 zN m |
| 5 lb ft | 6.77909e+21 zN m |
| 10 lb ft | 1.355818e+22 zN m |
| 50 lb ft | 6.77909e+22 zN m |
| 100 lb ft | 1.355818e+23 zN m |
| 500 lb ft | 6.77909e+23 zN m |
Reverse conversion: Zeptonewton meter to Pound-foot
1.355818e+21 zN m × 7.375621e-22 = 1.000000038 lb ft
1.355818e+21 zeptonewton meters = 1.000000038 pound-feet.
pound-feet = zeptonewton meters × 7.375621e-22
For a page dedicated to this direction, see Zeptonewton meter to Pound-foot.
Understanding the Pound-foot
Pound-foot (lb ft) measures torque. A pound-foot is the torque from one pound-force applied at one foot of leverage: exactly 1.3558179483314004 newton-meters. It is classified as a US/imperial customary unit.
Where it's used: United States (automotive and mechanical torque specifications)
Pound-foot vs. foot-pound. Pound-foot (torque) and foot-pound (energy/work) use the same two units but measure physically different quantities; US convention typically orders them differently to help distinguish which is meant, though usage isn't always consistent.
Uses of the Pound-foot today
- US torque wrench specifications (bolt tightening)
- US automotive engine torque specifications
- US mechanical and construction trades
History of the Pound-foot
The pound-foot follows from pound-force and the foot, both standardized through English and later international agreements, remaining the standard US automotive and mechanical torque unit even as most other measurements shifted toward metric in engineering contexts.
Historical origin. Pound-foot was not the invention of a single named person; it developed through the process described above.
Understanding the Zeptonewton meter (zN m)
Zeptonewton meter is 1e-21 newton meter units.
Pound-foot — sources
- NIST Special Publication 811 — Documents the pound-foot's exact newton-meter equivalence.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many zeptonewton meters are in 1 pound-foot?
1 pound-foot equals 1.355818e+21 zeptonewton meters, using the exact defined conversion factor rather than an estimate.
How do I convert pound-foot to zeptonewton meter?
Multiply the pound-foot value by 1.355818e+21. The converter above does this instantly to whatever precision you set.
How do I convert zeptonewton meter back to pound-foot?
Use the reverse factor: 1 zeptonewton meter equals 7.375621e-22 pound-feet. You can also use the swap control in the converter above to flip the direction instantly.
What is a pound-foot?
Pound-foot (lb ft) measures torque. A pound-foot is the torque from one pound-force applied at one foot of leverage: exactly 1.3558179483314004 newton-meters. It is classified as a US/imperial customary unit.
What is a zeptonewton meter?
Zeptonewton meter (zN m) is a unit of torque.
Is the pound-foot to zeptonewton meter conversion exact?
Yes. A pound-foot is the torque from one pound-force applied at one foot of leverage: exactly 1.3558179483314004 newton-meters. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.
What is the difference between pound-foot vs. foot-pound?
Pound-foot (torque) and foot-pound (energy/work) use the same two units but measure physically different quantities; US convention typically orders them differently to help distinguish which is meant, though usage isn't always consistent.
Where is the pound-foot still used today?
United States (automotive and mechanical torque specifications)