Convert Torque from Kilogram-centimeters to Pound-inches (kg-cm to lbf-in)

Kilogram-centimeter to Pound-inch Conversion Formula

Example

Let's convert 5 Kilogram-centimeter (kg-cm) to Pound-inch (lbf-in).

Using the formula:

Therefore, 5 Kilogram-centimeter (kg-cm) is equal to 4.339808145247106175 Pound-inch (lbf-in).

How many kilogram-centimeters are in one pound-inch? One Pound-inch (lbf-in) contains 1.1521246637310283405 Kilogram-centimeters (kg-cm) — the inverse of the factor above. Multiplying by 0.867961629049421235 takes you from kilogram-centimeters to pound-inches; multiplying by 1.1521246637310283405 brings you back.

Put in words: one kilogram-centimeter equals 0.867961629049421235 pound-inches, so the kilogram-centimeter is the smaller unit of this pair. Converting between them never changes the amount of torque being measured — only the size of the unit you count it in.

What Is a Kilogram-centimeter (kgf·cm)?

A kilogram-centimeter (kgf·cm) is one kilogram-force acting at one centimetre from the axis. It is one hundredth of a kilogram-meter.

• 1 kgf·cm = 0.0980665 N·m
• 1 kgf·m = 100 kgf·cm

The Hobby Servo Unit

If you have ever bought a hobby servo, you have seen this unit. Servo torque is published almost universally in kgf·cm — a common 9 g micro servo is rated around 1.8 kgf·cm, a standard-size servo around 10–20 kgf·cm.

The rating tells you how much weight the servo can hold at a given arm length: 10 kgf·cm means it can just support 10 kg at 1 cm from the shaft, or 1 kg at 10 cm, or 0.5 kg at 20 cm. Doubling the arm halves the load it can hold.

Where Kilogram-centimeter Is Used

• RC servos and hobby robotics — the dominant unit in datasheets and marketplaces.
• Small gearmotors sold through electronics suppliers.
• Legacy metric torque specifications for small fasteners.
• Tyre valve and small assembly torque figures on older equipment.

Converting Kilogram-centimeter

What Is a Pound-inch (lbf·in)?

A pound-inch (lbf·in) is one pound-force applied at one inch from the axis of rotation. It is the small-torque companion to the pound-foot.

• 1 lbf·ft = 12 lbf·in (exactly, since a foot is twelve inches)
• 1 lbf·in = 0.112985 N·m

Why a Smaller Imperial Unit Exists

Many fasteners are tightened to far less than one pound-foot. Writing "0.4 lbf·ft" invites a decimal-point error on a shop floor; writing "5 lbf·in" does not. Small-torque work therefore uses inch units almost exclusively.

Where Pound-inch Is Used

• Electrical terminals — breaker lugs and terminal blocks are specified in lbf·in, and both under- and overtightening cause failures.
• Electronics and instrument assembly — small screws in enclosures and connectors.
• Aerospace fasteners — small-diameter hardware throughout aircraft assembly.
• Optics, firearms and precision equipment — mounting screws where excess torque distorts the assembly.

Torque screwdrivers and small click wrenches are graduated in lbf·in for exactly this range.

A Common and Expensive Mistake

Confusing lbf·in with lbf·ft applies twelve times the intended torque. On a 5 lbf·in electrical terminal this shears the screw or crushes the conductor. Always check which unit the specification uses before setting a wrench.

Converting Pound-inch

Kilogram-centimeter to Pound-inch Conversion Table

Here are some quick reference conversions from Kilogram-centimeter (kg-cm) to Pound-inch (lbf-in):