Pounds-force to Millinewtons (lbf to mN)

1 pound-force equals 4,448.221615 millinewtons (rounded).

1 pound-force = 4,448.221615 millinewtons

How to convert pounds-force to millinewtons

To convert pounds-force to millinewtons, multiply the number of pounds-force by 4,448.221615. The factor is rounded to 10 significant digits. To go the other way, multiply millinewtons by 0.0002248089431 (rounded).

millinewtons = pounds-force × 4,448.221615

Example: 10 pounds-force = 44,482.21615 millinewtons.

About these units

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

Millinewton (mN)

Metric (SI)Current unit

One thousandth of a newton. Used for very small forces.

At the other end of the scale, a millinewton is one thousandth of a newton, a force so small that an apple weighing 200 g, which Wikipedia puts at about 1.96 N, would press down with nearly two thousand of them. The unit is the SI multiple 10^-3 N, formed with the prefix milli, and it suits measurements of delicate forces in laboratory work.

The abbreviation mN also appears in a closely related but different quantity. Surface tension is a force per unit length, so it is quoted in millinewtons per metre, and water at 20 degrees Celsius comes to about 72.8 mN/m. That figure equals 72.8 dyn/cm in the older centimetre-gram-second system, since one dyne per centimetre and one millinewton per metre are the same. In plain force terms, 1 mN is 100 dynes, or about 0.0000102 kilogram-force.

1 millinewton = 0.001 newtons (exactly).

Sources: Wikipedia: Newton (unit); Wikipedia: Surface tension

Related conversions

See all force units.