Question 1

How many Nm is 80 ft-lbs?

Accepted Answer

108.5 Nm. Multiply foot-pounds by 1.3558 to get Newton-metres. Other common wheel-nut figures: 90 ft-lb = 122 Nm, 100 ft-lb = 136 Nm, 140 ft-lb = 190 Nm.

Question 2

What is the exact conversion?

Accepted Answer

1 ft-lb = 1.355 817 948 Nm exactly, from the definitions of the foot (0.3048 m) and the pound-force (4.448 221 615 N). The reverse factor is 0.737 562 149 ft-lb per Nm.

Question 3

How do I set a Nm wrench from a ft-lb spec?

Accepted Answer

Convert and round to the wrench’s scale: 65 ft-lb → 88 Nm, set 88. Most click wrenches are accurate to about ±4 %, so rounding to the nearest whole Nm makes no practical difference.

Question 4

Is a Nm torque wrench better than a ft-lb one?

Accepted Answer

They measure the same thing; the difference is the scale. Because 1 Nm is a smaller unit, Nm scales have finer graduations, which helps on low-torque jobs. Many wrenches print both scales side by side.

Question 5

What about inch-pounds and kgf·m?

Accepted Answer

Inch-pounds are foot-pounds × 12 (80 ft-lb = 960 in-lb), used for small fasteners. Kilogram-force metres (kgf·m or kg·m) appear in older Japanese manuals: 1 kgf·m = 9.807 Nm = 7.233 ft-lb. The calculator shows all four.

ft-lb	N·m	in-lb
5	6.8	60
10	13.6	120
15	20.3	180
20	27.1	240
25	33.9	300
30	40.7	360
40	54.2	480
50	67.8	600
60	81.3	720
75	101.7	900
80	108.5	960
90	122	1,080
100	135.6	1,200
120	162.7	1,440
150	203.4	1,800
200	271.2	2,400

ft-lbs to Nm Converter

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