Pounds-force to Dynes (lbf to dyn)

1 pound-force equals 444,822.1615 dynes (rounded).

How to convert pounds-force to dynes

To convert pounds-force to dynes, multiply the number of pounds-force by 444,822.1615. The factor is rounded to 10 significant digits. To go the other way, multiply dynes by 0.000002248089431 (rounded).

dynes = pounds-force × 444,822.1615

Example: 10 pounds-force = 4,448,221.615 dynes.

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

Dyne (dyn)

CGS & old metricTraditional unit (still used in some regions)

Exactly 10⁻⁵ newtons, the CGS unit of force: one gram-centimeter per second squared.

Dyne derives from the Ancient Greek dynamis, meaning power or force. The name was first put forward in 1873 by a committee of the British Association for the Advancement of Science, a group that included James Clerk Maxwell and William Thomson, the future Lord Kelvin. They were choosing names for dynamical units built on the centimeter, gram and second, and the dyne became the force unit of that system.

By definition it is the force that gives a mass of one gram an acceleration of one centimeter per second squared. That is exactly 10 micronewtons, or 0.00001 newton, so 100,000 dynes make one newton. A kilogram-force is 980,665 dynes. Physicists still meet it in surface tension, where water at 25 degrees Celsius is about 72 dynes per centimeter. The pressure unit that goes with it is the barye, one dyne per square centimeter, and the unit of work is the erg.

1 dyne = 0.00001 newtons (exactly).

Sources: Wikipedia: Dyne; Wikipedia: Centimetre-gram-second system of units; NIST SP 811, Appendix B.8 conversion factors

Related conversions

See all force units.