ft-lbs to Nm: the conversion mechanics need to know

American shops talk in pound-feet. European service manuals talk in newton-meters. Japanese factory documents do both. If you wrench across brands, you live at the intersection of those units. Here is the math, the rounding rules, and a printable lookup table that saves you from a phone calculator when your hands are dirty.

The conversion in one line

One pound-foot equals approximately 1.355818 Nm. Or, the other way: one newton-meter equals approximately 0.737562 ft-lbs.

For shop work, the practical rounded factors are:

• ft-lbs → Nm: multiply by 1.356
• Nm → ft-lbs: multiply by 0.738

Where the conversion factor comes from

Torque is force times distance — a moment about an axis. One pound of force at one foot of lever arm is one pound-foot. One newton of force at one meter of lever arm is one newton-meter. To convert, you convert both: pounds to newtons (multiply by 4.4482) and feet to meters (multiply by 0.3048). Multiply those two together and you get 1.3558. That is the conversion factor.

Most service manuals round to three or four significant figures. So if you see a Toyota spec listed as “25 Nm (18 ft-lbs),” the math is 25 × 0.737562 = 18.44, rounded to 18. The Toyota engineer did not invent a separate number for the parenthetical — they applied the same factor you would.

Why rounding matters on small fasteners

Conversion error compounds at the low end. Examples:

• A spec of 10 Nm is 7.4 ft-lbs, not 7. If you round to 7 and your wrench reads in 0.5-ft-lb increments, you are torquing to 95% of spec. Acceptable for most joints. Not acceptable on a magnesium valve cover or a fragile plastic intake-manifold bolt.
• A spec of 5 Nm is 3.7 ft-lbs, or about 44 in-lbs. At this range you should be using an inch-pound wrench, not a ft-lb wrench. A 1/2-drive ft-lb wrench has too much breakaway error to read this accurately.
• A spec of 2 Nm is 17.7 in-lbs. This is in the range of a beam-type inch-pound wrench. A click-type at this setting often clicks at the spring preload, not the actual torque. Use a beam.

At the high end the rounding rarely matters. A 100-ft-lb spec converts to 135.6 Nm. Rounding to 136 or 135 is half a percent. Within the wrench's accuracy.

Read the wrench, not the calculator

Most quality torque wrenches read in increments of:

• 1/4-inch drive — 10 in-lbs or 1 Nm.
• 3/8-inch drive — 0.5 ft-lbs or 1 Nm.
• 1/2-inch drive — 1–2 ft-lbs or 2 Nm.
• 3/4-inch drive — 5 ft-lbs or 5–10 Nm.

If your converted value lands between two markings, round to the nearest marking toward the manufacturer's stated unit. So if the manual says 25 Nm and your wrench is in ft-lbs reading 0.5-ft-lb increments, set 18.5. Do not set 19 because that is “close enough” — half a foot-pound over spec on a 25-Nm head-cover bolt cracks the casting on plenty of engines.

Quick lookup table

Print this and tape it inside the toolbox lid. Values rounded for shop use.

Common ft-lbs to Nm

• 5 ft-lbs → 6.8 Nm
• 10 ft-lbs → 13.6 Nm
• 15 ft-lbs → 20.3 Nm
• 20 ft-lbs → 27.1 Nm
• 25 ft-lbs → 33.9 Nm
• 30 ft-lbs → 40.7 Nm
• 35 ft-lbs → 47.5 Nm
• 40 ft-lbs → 54.2 Nm
• 50 ft-lbs → 67.8 Nm
• 60 ft-lbs → 81.3 Nm
• 70 ft-lbs → 94.9 Nm
• 80 ft-lbs → 108.5 Nm
• 90 ft-lbs → 122.0 Nm
• 100 ft-lbs → 135.6 Nm
• 125 ft-lbs → 169.5 Nm
• 150 ft-lbs → 203.4 Nm

Common Nm to ft-lbs

• 5 Nm → 3.7 ft-lbs
• 10 Nm → 7.4 ft-lbs
• 15 Nm → 11.1 ft-lbs
• 20 Nm → 14.8 ft-lbs
• 25 Nm → 18.4 ft-lbs
• 30 Nm → 22.1 ft-lbs
• 40 Nm → 29.5 ft-lbs
• 50 Nm → 36.9 ft-lbs
• 60 Nm → 44.3 ft-lbs
• 75 Nm → 55.3 ft-lbs
• 100 Nm → 73.8 ft-lbs
• 120 Nm → 88.5 ft-lbs
• 150 Nm → 110.6 ft-lbs
• 200 Nm → 147.5 ft-lbs

Inch-pounds, foot-pounds, and the trap

One foot-pound is 12 inch-pounds. Easy. The trap is that small specs in American manuals get listed in inch-pounds and then a forum thread “helpfully” translates them to foot-pounds incorrectly. If someone tells you a fuel-rail bolt torques to 89 ft-lbs on a four-cylinder, they have probably converted from89 in-lbs wrong. Sanity-check at the wrench: 89 ft-lbs on an 8mm bolt will shear it the moment the click lands.

How Torq handles units

In Torq every spec is stored in the unit the OEM manual publishes. The display toggles between ft-lbs and Nm without rounding to a different nominal value than the source — so if the FSM lists 25 Nm and you flip to ft-lbs, you see 18.4, not 18. Staged specs (the 22 ft-lbs, +90°, +90°kind) preserve each stage's native unit; only the linear stages convert.

That sounds like a small thing. It is the difference between “close enough” and “correct.”