Ounces-force to Pounds-force (ozf to lbf)

1 ounce-force equals 0.0625 pounds-force exactly.

1 ounce-force = 0.0625 pounds-force

How to convert ounces-force to pounds-force

To convert ounces-force to pounds-force, multiply the number of ounces-force by 0.0625. This factor is exact. To go the other way, multiply pounds-force by 16.

pounds-force = ounces-force × 0.0625

Example: 10 ounces-force = 0.625 pounds-force.

About these units

Ounce-force (ozf)

US & ImperialCurrent unit

One sixteenth of a pound-force (0.278 N).

Defined as a sixteenth of a pound-force, the ounce-force is a small US customary unit of force. The pound-force is 0.45359237 kg times standard gravity of 9.80665 m/s2, which gives 4.4482216 N, so the ounce-force comes to about 0.2780139 N. NIST lists the same factor, and it is the figure used here.

The name borrows from the avoirdupois ounce, so the unit measures the weight of that much mass under standard gravity rather than a separate invented quantity. Twelve ounces-force is three quarters of a pound-force, about 3.34 N, and sixteen make a pound-force. NIST advises against using such non-SI units in its own publications, and the metric equivalent for light forces is the millinewton, since one ounce-force is roughly 278 mN.

1 ounce-force = 0.278013851 newtons (approximately).

Sources: NIST SP 811, Appendix B.8; Wikipedia: Pound (force)

Pound-force (lbf)

US & ImperialCurrent unit

Exactly 4.4482216152605 newtons: the weight of a one-pound mass under standard gravity. The US unit of force.

People have used the pound-force since the eighteenth century for low-precision work, long before anyone needed to define it carefully. A pound of material on Earth's surface pulls with about a pound of force, which made it convenient to treat the two as one. The twentieth century demanded a precise definition: one pound-force is the avoirdupois pound, exactly 0.45359237 kg, multiplied by standard gravity of 9.80665 meters per second squared, which comes to about 4.448 newtons.

Because the unit is not simply mass times acceleration in its own system, formulas in English engineering units need a conversion constant of about 32.174 pound-feet per pound-force second squared. A slug, 32.174049 pounds of mass, is what one pound-force accelerates at one foot per second squared. In the US, jet and rocket thrust is often given as pounds of thrust: each Space Shuttle solid rocket booster produced 3,300,000 pounds-force. Earth's gravity varies by up to about half a percent between equator and pole, which low-precision work can ignore.

1 pound-force = 4.448221615 newtons (approximately).

Sources: Wikipedia: Pound (force); NIST Guide to the SI, Appendix B.8: conversion factors

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