Inch-Pounds to Foot-Pounds Converter
Enter a torque value in inch-pounds and get the equivalent in foot-pounds, Newton-metres, and kilogram-force centimetres instantly. Switch direction to convert foot-pounds back to inch-pounds. A step-by-step breakdown and a reference table of common fastener torque specs are included.
Formula
Worked example
A torque wrench spec of 89 in-lb: divide 89 by 12 to get 7.417 ft-lb. In Newton-metres: 7.417 x 1.3558 = 10.055 Nm. Reverse check: 7.417 x 12 = 89.0 in-lb.
How to convert inch-pounds to foot-pounds
The conversion is a single arithmetic step: divide the inch-pound value by 12. The factor of 12 comes from the definition of the foot - one foot equals twelve inches, so one foot-pound of torque is twelve times larger than one inch-pound. For the reverse, multiply foot-pounds by 12 to recover inch-pounds. Because the relationship is exact, no rounding is introduced by the unit change itself; any rounding you see is purely a display choice. Formula: ft-lb = in-lb / 12. Reverse: in-lb = ft-lb x 12.
What are inch-pounds and foot-pounds?
Both are non-SI units of torque (rotational force) used widely in the United States and in the automotive industry worldwide. Torque is the product of a force and the perpendicular distance from the pivot point (radius). An inch-pound is the torque produced by 1 pound-force applied at a radius of 1 inch. A foot-pound is the same force applied at a radius of 1 foot, making it exactly 12 times larger. In technical literature you will also see them written as "pound-force inch" (lbf-in) and "pound-force foot" (lbf-ft), which are more precise because they name the force unit explicitly rather than the mass unit. The SI equivalent is the Newton-metre (Nm): 1 ft-lb equals approximately 1.3558 Nm. Many modern torque wrenches and specifications list values in both ft-lb and Nm to serve international markets.
When to use in-lb vs ft-lb
In-lb is preferred for small, precise fasteners where foot-pounds would produce inconveniently small decimal values. You will see in-lb in electronics assembly, small engine work (fuel injectors, sensors), bicycle maintenance, and anything with bolts smaller than about 1/4 inch. Foot-pounds dominate for larger fasteners: wheel lug nuts, suspension components, cylinder head bolts, and drivetrain hardware. When a torque spec gives a number below about 15 ft-lb, the same manufacturer will often list it in in-lb in an alternate column to avoid the decimal, for example 10.8 ft-lb is more clearly expressed as 130 in-lb on a torque wrench with in-lb markings.
Converting to Newton-metres and other units
This converter also outputs Newton-metres and kilogram-force centimetres. To go from ft-lb to Nm, multiply by 1.3558179483. To go from in-lb to Nm directly, multiply by 0.1129848. Kilogram-force centimetres (kgf-cm) appear in older Japanese and European service manuals: 1 ft-lb = 13.8255 kgf-cm and 1 in-lb = 1.15212 kgf-cm. Having all three in one calculation is particularly useful when working from an imported vehicle service manual that mixes unit systems.
Common torque specifications
| Application | Torque (in-lb) | Torque (ft-lb) | Torque (Nm) |
|---|---|---|---|
| Small electronics / circuit board screws | 2-5 | 0.17-0.42 | 0.23-0.56 |
| Oil drain plug (small engine) | 120-180 | 10-15 | 13.6-20.3 |
| Spark plugs (aluminum head) | 132-168 | 11-14 | 14.9-19.0 |
| Wheel lug nuts (compact car) | 720-1080 | 60-90 | 81.3-122 |
| Cylinder head bolts (typical) | 1200-2400 | 100-200 | 135-271 |
| Suspension strut top nut | 240-360 | 20-30 | 27.1-40.7 |
| Brake caliper bolts | 180-480 | 15-40 | 20.3-54.2 |
| Engine mounts | 360-600 | 30-50 | 40.7-67.8 |
| Transmission drain plug | 144-240 | 12-20 | 16.3-27.1 |
| Battery terminal bolts | 12-24 | 1-2 | 1.36-2.71 |
Typical torque values for common fasteners and applications. Always verify against the official service manual for your specific application.
Frequently asked questions
How many inch-pounds are in a foot-pound?
Exactly 12 inch-pounds equal 1 foot-pound. The factor is exact, not approximate, because 1 foot is defined as exactly 12 inches. So to convert in-lb to ft-lb you divide by 12, and to convert ft-lb to in-lb you multiply by 12.
What is 89 in-lb in foot-pounds?
89 in-lb divided by 12 equals 7.4167 ft-lb. This is a common spec for spark plugs in many engines. On a torque wrench calibrated in ft-lb you would set it to 7.4 ft-lb (or use a wrench with in-lb markings set to 89).
Is ft-lb the same as lb-ft?
Yes, ft-lb and lb-ft refer to the same unit of torque. "Pound-foot" (lb-ft) is technically the more correct name in physics, because torque is force times distance and the force (pounds) should come first. However, ft-lb is extremely common in workshop manuals and on torque wrench labels, and both terms are used interchangeably in practice.
How do I convert foot-pounds to Newton-metres?
Multiply foot-pounds by 1.3558 to get Newton-metres. For example, 50 ft-lb x 1.3558 = 67.79 Nm. To go the other direction, divide Newton-metres by 1.3558 (or multiply by 0.7376) to get foot-pounds. This converter shows Nm alongside ft-lb and in-lb so you do not need to do this step separately.
Can I use this converter for both directions?
Yes. Use the "Conversion direction" selector at the top of the calculator to switch between in-lb to ft-lb and ft-lb to in-lb. Both directions use the same exact factor (12) and the Newton-metre and kgf-cm outputs update automatically in both modes.
What is the difference between torque and energy, and do they share the same units?
Torque and energy are dimensionally the same (force times distance) but physically different concepts. Energy (or work) is a scalar; torque is a vector that describes rotational tendency. In SI, both are measured in Newton-metres (Nm), but in the imperial system the convention is to use "foot-pounds" for energy and "pound-feet" for torque to avoid confusion. In everyday workshop use this distinction is rarely observed and both terms are used interchangeably.