Foot-pounds to newton meters (ft-lb to N·m) converter

What is a foot-pounds to newton meters converter?

A foot-pounds to newton meters converter is an online tool that translates a torque value expressed in foot-pounds (lbf·ft) into its equivalent in newton meters (N·m), and back again. Both units describe torque: the rotational, or twisting, effect produced when a force acts at a distance from a pivot. The foot-pound belongs to the imperial system and is widely used in the United States, while the newton meter is the SI unit used almost everywhere else and throughout engineering literature. This converter bridges the two systems so a value quoted in one can be applied confidently in the other.

Foot-pounds and newton meters

A foot-pound of torque is the twist produced by a one-pound force acting one foot from the axis of rotation. A newton meter is the twist produced by a one-newton force acting one meter from the axis. Because a pound-force is larger than a newton but a foot is shorter than a meter, one foot-pound works out to roughly 1.36 newton meters. Note that “foot-pound” here means torque (lbf·ft); the same name is sometimes used loosely for the unit of energy, but torque and energy are physically distinct quantities even though they share dimensions.

Practical application

Converting between foot-pounds and newton meters matters whenever a single specification has to serve audiences using different unit systems:

• Automotive servicing: Wheel lug nuts, head bolts, and spark plugs are torqued to manufacturer specs that may be listed in either ft-lb or N·m.
• Mechanical engineering: Fastener torque charts and shaft-load calculations move between imperial and SI depending on the standard being followed.
• Tool calibration: Torque wrenches are sold with scales in one unit or both, so technicians often re-express a target value.
• International collaboration: Drawings and assembly instructions shared across borders need consistent torque units to avoid over- or under-tightening.

Formula for conversion

To convert between foot-pounds and newton meters, use the following relationships:

For foot-pounds to newton meters: $\text{N·m} = \text{lbf·ft} \times 1.355818$

For newton meters to foot-pounds: $\text{lbf·ft} = \text{N·m} \times 0.737562$

The factor 1.355818 comes from the exact definition of the pound-force (4.4482216152605 N) multiplied by the length of a foot (0.3048 m). The reverse factor 0.737562 is simply its reciprocal.

Foot-pounds to newton meters conversion table

The following table lists common torque values in foot-pounds with their newton meter equivalents, plus the related inch-pound and kilogram-force meter values for reference:

Examples

Example 1: Converting 1 foot-pound

Convert a single foot-pound of torque to newton meters using the factor 1.355818:

$1 \text{ lbf·ft} \times 1.355818 = 1.355818 \text{ N·m}$

So one foot-pound is about 1.36 newton meters.

Example 2: Converting back from newton meters

Going the other way, convert 1 newton meter to foot-pounds with the reciprocal factor 0.737562:

$1 \text{ N·m} \times 0.737562 = 0.737562 \text{ lbf·ft}$

A single newton meter is therefore roughly 0.74 foot-pounds.

Example 3: A typical fastener spec

Suppose a torque wrench should be set to 10 foot-pounds but the wrench reads in newton meters. Multiply by the conversion factor:

$10 \text{ lbf·ft} \times 1.355818 = 13.558 \text{ N·m}$

You would set the wrench to about 13.56 N·m.

Example 4: Foot-pounds to kilogram-force meters

If a spec is given in the older kilogram-force meter unit, convert through newton meters (1 kgf·m = 9.80665 N·m):

$1 \text{ lbf·ft} \times \frac{1.355818}{9.80665} = 0.138255 \text{ kgf·m}$

One foot-pound is close to 0.138 kgf·m.

Notes

• Foot-pound torque (lbf·ft) and inch-pound torque (lbf·in) differ by a factor of 12, since one foot equals twelve inches.
• Although torque and energy share the same physical dimensions, never mix a torque value with an energy value; they answer different physical questions.
• The exact factor is 1.3558179483314004 N·m per lbf·ft; rounding to 1.355818 is accurate enough for nearly all practical work.
• When following a tightening specification, always use the unit the manufacturer intended to avoid damaging fasteners.

Frequently asked questions

How many newton meters are in one foot-pound?

One foot-pound of torque equals approximately 1.355818 newton meters. Multiply any foot-pound value by this factor to get newton meters.

How do I convert newton meters back to foot-pounds?

Multiply the newton meter value by 0.737562. For example, 1 N·m is about 0.74 lbf·ft. If you start from newton meters, you can also use our newton meters to foot-pounds converter.

Is a foot-pound of torque the same as a foot-pound of energy?

No. The name is shared because the units have the same dimensions, but torque measures a twisting effect while energy measures work done. They are not interchangeable in calculations.

How many newton meters is 10 foot-pounds?

Ten foot-pounds equals about 13.56 newton meters (10 × 1.355818 = 13.558). This is a common range for smaller fasteners.

What is the difference between foot-pounds and inch-pounds?

Both measure torque, but a foot-pound is twelve times larger than an inch-pound because a foot is twelve inches. To convert foot-pounds to inch-pounds, multiply by 12. For inch-pound torque you can use our inch-pounds to newton meters converter.

Why is precision important when converting torque?

Fasteners are designed to be tightened within a narrow torque window. A small conversion error can leave a joint loose or stretch a bolt past its limit, so it is worth carrying enough decimal places when converting between units.