Torque Conversion Calculator
Convert between foot-pounds, newton-metres and inch-pounds. Then work out what to set the wrench to when you are using a crowfoot or an extension.
Convert a torque figure
- The extension correction only applies to adapters that extend in line with the handle, such as a crowfoot pointing straight ahead.
- A crowfoot turned 90 degrees to the handle changes the length by almost nothing. No correction needed.
- A plain socket extension pointing down at the fastener does not change the lever arm at all.
The conversions
One foot-pound is 1.3558 newton-metres and 12 inch-pounds. Service manuals mix all three, often on the same page, and small fasteners are almost always specified in inch-pounds because the numbers get awkward otherwise. A 60 in-lb bolt is 5 ft-lb, which is barely more than finger tight.
Watch for that one. Reading 60 as foot-pounds instead of inch-pounds applies twelve times the intended torque, which will snap the bolt or strip the thread.
Why an extension changes the setting
A torque wrench measures the twist at its own head. Put a crowfoot on the end pointing straight ahead and the fastener is now further from your hand than the wrench thinks it is. The lever arm got longer, so the fastener sees more torque than the dial says.
Correcting for it is one multiplication. Take the wrench length, divide by the wrench length plus the offset, and multiply your target torque by that. A 90 ft-lb target through a 2 inch crowfoot on an 18 inch wrench means setting the wrench to 81.
When you do not need to correct
Turn the crowfoot 90 degrees to the handle and the effective length barely changes, so no correction is needed. That is the easy way out and it is what most techs do. A normal socket extension pointing down at the bolt does not change the lever arm either, no matter how long it is.
Frequently asked questions
How many Nm is 80 ft-lb?
108.5 Nm. Multiply foot-pounds by 1.3558 to get newton-metres, or divide newton-metres by 1.3558 to go the other way.
Do I need to adjust torque when using an extension?
Only if the adapter moves the fastener further along the handle. A crowfoot pointing straight ahead does, and needs correcting. A crowfoot at 90 degrees and any ordinary socket extension pointing down at the bolt do not.
Where do I measure wrench length from?
From the centre of the drive square to the centre of where your hand sits on the grip. Not the very end of the handle. Holding the wrench in a different spot than you measured is a bigger error than most people expect.
Should I store a click wrench at its lowest setting?
Wind it down to the bottom of its range, not to zero. That takes the load off the spring without unseating the mechanism. Leaving one wound up to 150 ft-lb in a toolbox for a year is how they drift out of calibration.
Everything on this page is an estimate worked out from the numbers you entered and typical figures for the conditions you picked. Your vehicle, your parts and your conditions will differ. Check anything you intend to act on against the manufacturer's specification, the service manual, or a qualified technician. Verifying the result before relying on it is up to you.