Tonnes-force to Pounds-force (tf to lbf)

1 tonne-force equals 2,204.622622 pounds-force (rounded).

How to convert tonnes-force to pounds-force

To convert tonnes-force to pounds-force, multiply the number of tonnes-force by 2,204.622622. The factor is rounded to 10 significant digits. To go the other way, multiply pounds-force by 0.00045359237.

pounds-force = tonnes-force × 2,204.622622

Example: 10 tonnes-force = 22,046.22622 pounds-force.

About these units

Tonne-force (tf)

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

Exactly 9,806.65 newtons, the weight of one metric tonne at standard gravity.

Heavy structures and presses call for a force unit scaled to match, and the tonne-force supplies it: the weight of one metric tonne, which is 1,000 kilograms-force. Other names for it are metric ton-force, megagram-force and megapond. Using exactly 9.80665 newtons per kilogram-force, it comes to 9,806.65 newtons, or about 9.8 kilonewtons.

Do not confuse it with the ton-force of US customary practice. NIST gives the short ton-force, based on 2,000 pounds-force, as 8,896.443 newtons, and the metric unit is about 10 percent larger. The tonne-force belongs to the same deprecated gravitational metric family as the kilogram-force and has no place in SI, where the kilonewton and meganewton are used instead. NIST tables have no entry for the metric version, so its value here comes from the kilogram-force definition.

1 tonne-force = 9,806.65 newtons (exactly).

Sources: Wikipedia: Kilogram-force; NIST SP 811, Appendix B.8 conversion factors

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

Related conversions

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