Torque Specs: in-lbs vs ft-lbs on Cordless Tools
Tool class determines the unit. Impact drivers publish inch-pounds, impact wrenches foot-pounds. One foot-pound equals twelve inch-pounds.
Torque units signal tool class: impact drivers are rated in inch-pounds (in-lbs, typically 1,400–2,500), impact wrenches in foot-pounds (ft-lbs, roughly 100 to 1,000+), and drills report a lower in-lbs figure at their low-speed setting where torque peaks and speed drops. To compare across units, divide ft-lbs figures by 12 to get in-lbs (or multiply in-lbs by 12 for ft-lbs) — a 400 ft-lb impact wrench equals 4,800 in-lbs, roughly double even a strong impact driver's output, which is why wrenches and drivers aren't interchangeable for lug nuts versus deck screws.