Torque Converter

This converter moves a torque value between the five units the tool supports: newton-metres, kilogram-force metres, pound-force feet, pound-force inches and dyne-centimetres. Enter the figure, choose the unit it is in and the unit you want, and read the result.

Torque is a twisting force — a force applied at a distance from a pivot. That is why every unit is a force multiplied by a length, and why the numbers are so easy to get wrong when the two halves come from different measurement systems.

Why does a workshop need this at all?

Because fastener specifications and the tools used to meet them frequently come from different countries. A Japanese motorcycle service manual lists torque in newton-metres. The click wrench in a British or American garage is very often calibrated in pound-feet. A vintage European manual may use kilogram-force metres. All three describe the same physical tightness, and guessing between them is how bolts get stripped or left loose.

Under-tightening lets a joint work loose under vibration. Over-tightening stretches the fastener past its elastic limit, so it no longer holds clamping load even though it feels tight. Neither failure is obvious at the time, which is why the specified figure is worth converting properly rather than approximating.

A worked example: wheel nuts

A car manual specifies 115 N·m for the wheel nuts, and your torque wrench reads in pound-feet. One pound-force foot is 1.35582 newton-metres, so:

• 115 ÷ 1.35582 = 84.8 lbf·ft

Set the wrench to 85 and you are within a fraction of a percent of the specification. Going the other way, a bolt specified at 85 lbf·ft is 85 × 1.35582 = 115.24 N·m.

A second one worth knowing: 200 N·m ÷ 1.35582 = 147.5 lbf·ft. And one kilogram-force metre is exactly 9.80665 N·m, because it is one kilogram of force — that is, standard gravity acting on a kilogram — at one metre.

Pound-feet and foot-pounds

You will see torque written both ways, and in practice people use them interchangeably. Strictly, torque is pound-force feet (lbf·ft) and energy is foot-pounds (ft·lb). They have the same dimensions but describe different things: torque is a twist, energy is work done. No unit converter can tell them apart, so the distinction is on you when reading a specification.

The one place it genuinely matters is where a document lists both — an engine's torque output and its energy consumption, say. If the numbers seem impossible, check which quantity you are looking at before checking the arithmetic.

How to use the converter

1. Enter your torque value in the input box.
2. Select the unit the specification is written in.
3. Select the unit your wrench or document uses.
4. Read the converted figure, and round to whatever your wrench can actually be set to.

Where each unit tends to show up

• Newton-metre (N·m) — the SI unit. Almost all modern engineering and most current vehicle manuals.
• Pound-force foot (lbf·ft) — North American automotive and construction work, and most torque wrenches sold there.
• Pound-force inch (lbf·in) — small fasteners, electronics, aircraft work. Twelve lbf·in to the lbf·ft.
• Kilogram-force metre (kgf·m) — older European and Japanese documentation.
• Dyne-centimetre — the CGS unit, essentially only seen in physics texts. One dyne-centimetre is 10^-7 N·m.

Frequently asked questions

How many newton-metres is one pound-foot?

1.35582. For quick mental work, multiplying by 1.36 gets you within a tenth of a percent, which is finer than most torque wrenches can be set anyway.

Is kgf·m the same as kg·m?

People write both, but only the first is meaningful. A kilogram is mass, not force; kilogram-force means the weight of a kilogram under standard gravity, 9.80665 newtons. Documents that write kg·m almost always mean kgf·m.

Does torque converted this way account for lubrication?

No, and that matters. A torque figure assumes a specific thread condition. Oiling a thread that was specified dry can increase the actual clamping force by 20% or more at the same wrench setting. Convert the number, but follow the manual on whether the thread should be dry, oiled or thread-locked.

Why do some specifications give a range?

Because the tolerance is real and the wrench has its own error. If a manual says 100–110 N·m, converting both ends of the range is safer than converting the midpoint and hoping.

Can I use this for torque wrench calibration?

For reading across units, yes. For actual calibration you need a reference transducer — unit conversion tells you what the target is, not whether your tool is delivering it.

Related tools

• Power Converter — torque and power are two halves of the same engine specification.
• Weight Converter — for the force half of the unit.
• Length Converter — for the distance half.
• Pressure Converter — the other specification that arrives in mixed units.