Ft-Lbs to Nm Torque Converter

How to use this converter

1. Type into any field — ft-lb, N·m, or in-lb. The other two recompute live as you type. No "Calculate" button.
2. Tap a quick-fill chip for the most common automotive torques — lug nuts (80 to 140 ft-lb), spark plugs (15 ft-lb), oil drain plugs (25 to 35 ft-lb), brake calipers (75 to 100 ft-lb). The ft-lb field fills, N·m and in-lb update, and the wrench-class chip tells you which drive size you should be reaching for.
3. Read the wrench-class chip. "Light fastener" means a 1/4" drive in-lb wrench. "Lug nut / suspension" means a 1/2" drive click-style. "Heavy" means a long-handle 1/2" or 3/4" drive. The summary line tells you what the value typically means in a real garage.
4. Save it. Hit "Share" to copy a link with your value preserved (paste it into a forum thread or text it to yourself), or "PDF" for a one-page conversion summary with a wrench-class chart and a star-pattern reminder.

Why this converter is different from generic ft-lb-to-Nm tools

The top results for "ft lbs to nm" are generic engineering converters. You type a number, you get a number, you leave. They don't know you're trying to torque a lug nut, a spark plug, or a brake caliper. They don't tell you which drive-size wrench to reach for. They don't show in-lb at all, which is the unit you actually need below 25 ft-lb. Here's what we did differently:

• Mechanic-flavored presets, not generic. Two rows of quick-fill chips above the inputs — one for lug nuts (80 / 100 / 120 / 140 ft-lb), one for common service torques (sensors, spark plugs, oil drain plugs, brake calipers). Tap one and you get the full conversion plus a "this is typically a [fastener]" tooltip.
• Three units linked, real-time. ft-lb, N·m, and in-lb are three connected inputs. Edit any one, the other two recompute live. Misumi has two separate calculators on the same page; everyone else is one direction. In-lb is the missing piece — under 25 ft-lb, your ft-lb wrench is in the bottom 20% of its range and reads inaccurately. You need an in-lb wrench, and you need to convert.
• Wrench-class chip on every result. "Light fastener — 1/4" drive click wrench (5–25 ft-lb)" or "Lug nut / suspension — 1/2" drive (30–250 ft-lb)." Generic converters give you a number; this tool tells you what tool to grab.
• NIST-exact factor. We use 1.3558179483 (NIST SP 811, exact-conversion table) — same factor referenced by xConvert, Misumi, and Inch Calculator, but rounded to nine decimals internally so 100 ft·lb round-trips back to exactly 100 (not 99.99). At lug-nut torque the difference is rounding noise; at industrial torque (250+ ft·lb) the cheap factor drifts.
• Branded printable summary. One-page PDF with your three values, the wrench-class chip, the lug-nut star-pattern reminder, and a vehicle/fastener fill-in line. Take it to the bay or stick it on the toolbox.
• Reviewed by an ASE Master Tech. Most converter sites are anonymous engineering blogs. Mike Reeves has 15 years in the bay and signs his name to the math — and to the wrench picks.
• Embeddable, free, no signup. Forum mods, build-thread pinned posts, motorcycle communities, Tacoma / Wrangler / Miata groups — copy a one-line snippet, host the same tool on your page with attribution.

How this converter works (the math)

Torque is force times the perpendicular distance from the axis of rotation. The foot-pound (ft·lb, also written lb-ft) is the imperial unit — one pound of force at the end of a one-foot wrench. The newton-meter (N·m) is the SI unit — one newton at the end of a one-meter wrench. Inch-pounds (in-lb) are exactly 1/12 of a foot-pound. The conversion is one constant, but it matters which one you use.

Ft-lb to Nm

Nm = ftLb × 1.3558179483

At common service torques, multiplying by 1.36 gets you within rounding of a click-style wrench's accuracy (typically ±4%). But at industrial torques (250+ ft·lb) the cheap rounded factor drifts visibly. We use full NIST precision internally and round the displayed number for human readability. So 100 ft·lb is 135.58 N·m, not 136.

Nm to ft-lb

ftLb = Nm / 1.3558179483

Same factor, inverted. So 250 N·m (a common European axle-bolt spec) is 184.39 ft·lb — well into the long-handle 1/2" or 3/4" drive range. The "how many ft-lbs is 1 Nm?" question (a popular search) answers 0.74 — useful when you're reading a German or Japanese factory manual and your wrench is American-made.

Ft-lb to in-lb (and back)

inLb = ftLb × 12 · ftLb = inLb / 12 (both exact, by definition).

This conversion is exact — twelve inches in a foot. So 25 ft·lb is exactly 300 in-lb. Why this matters: if your fastener spec is 18 ft·lb (a typical aluminum-head spark plug) and your only wrench is an in-lb model that goes to 250 in-lb, you can convert (216 in-lb) and use the in-lb wrench, which is more accurate at that force than a ft-lb wrench would be at the bottom of its range.

Sources used

Conversion factor is from NIST SP 811 (the US government's authoritative SI guide). Cross-checked against the BIPM SI Brochure (the international standard). Common automotive lug-nut and spark-plug ranges from Engineering Toolbox and the Speedway Motors lug-nut spec chart. The full fixture file with 20 test cases (every PAA-confirmed conversion plus boundary cases) lives at fixtures.json next to the component, and runs in CI on every build.

Common automotive torque values

Spark plugs: 12 to 25 ft·lb (16 to 34 N·m)

Most modern aluminum heads spec 12 to 18 ft·lb on a tapered-seat plug, or 25 to 33 ft·lb on a gasket-seat plug. Below 25 ft·lb, your standard ft-lb torque wrench is at the bottom of its range and reads inaccurately. Convert to in-lb (15 ft·lb = 180 in-lb) and use a 1/4" drive in-lb wrench instead. Cast-iron heads tolerate higher torque without stripping; aluminum heads punish over-torque ruthlessly — repair is a Time-Sert insert, $20 in tools and an hour you didn't plan for.

Oil drain plugs: 25 to 35 ft·lb (34 to 47 N·m)

Most cars spec 25 to 30 ft·lb on a steel pan; heavy-duty trucks and diesels run closer to 35 ft·lb. Aluminum oil pans (some BMW, Honda, and Subaru) drop to 18 to 22 ft·lb because the threads strip more easily. Always replace the crush washer — a fresh washer is the only way the spec torque actually seals. The "should I use a torque wrench on the drain plug?" question gets dismissed as overkill, but stripped pans are a $400 to $1,200 repair and a torque wrench is $40.

Lug nuts: 80 to 140 ft·lb (108 to 190 N·m)

Compact cars (Civic, Mazda3, Subaru Impreza, most Toyota): 70 to 80 ft·lb on a 12mm × 1.25 or 12mm × 1.5 stud. Mid-size sedans and crossovers (Camry, RAV4, CR-V, MDX): 80 to 95 ft·lb on a 14mm × 1.5 stud. Full-size SUVs and German performance: 100 to 120 ft·lb on a 14mm × 2.0 stud. Heavy trucks (F-150, Silverado 1500): 110 to 140 ft·lb on a 9/16" × 18 stud. Always star-pattern, two passes — snug to half spec on pass one, full spec on pass two. Re-torque after 25 to 50 miles on new wheels or aluminum / mag wheels.

Brake calipers: 25 to 130 ft·lb (34 to 176 N·m)

Caliper guide pins are usually 25 to 35 ft·lb. Caliper bracket bolts (the bigger ones holding the bracket to the spindle) are usually 75 to 130 ft·lb depending on vehicle. These vary widely — always check service data. Wrong torque on a caliper bracket is a spongy pedal at best and a loose caliper at worst.

Wheel-bearing nuts and axle nuts: 100 to 250+ ft·lb

Front-wheel-drive axle nuts can spec 200 to 250+ ft·lb (sometimes higher) depending on year and model. These need a 3/4" drive torque wrench plus a breaker bar to install — a 1/2" drive wrench at the top of its range is at risk of inaccuracy and the wrench itself is at risk of failure. Always verify the spec from a service manual; outdated forum posts under-spec these badly.

Common conversions: ft-lb to N·m to in-lb

Quick-reference for the values searches most often ask for. Every row is generated from the same NIST factor used by the calculator above. For values not listed, type into the calculator — it covers up to 100,000 ft·lb.

Frequently asked questions

How do you convert ft-lbs to Nm?

Multiply ft-lbs by 1.3558179483 (the NIST conversion factor). For example, 100 ft·lb × 1.3558 = 135.58 N·m. Going the other way: divide N·m by 1.3558179483 (or multiply by 0.7376). The calculator above does both directions plus inch-pounds in a single live three-way input.

How many foot-pounds is 1 N·m?

1 N·m equals 0.7376 ft·lb. A common rule of thumb is "Nm is about three-quarters of a ft·lb." That's accurate enough for back-of-napkin conversions — for actual torquing, use the full factor (the calculator above does it for you).

What is 27 ft-lbs in N·m?

27 ft·lb = 36.61 N·m. This is a common spark-plug spec on cast-iron heads and a common lower-bound value on caliper guide pins. At this torque you should be using a 3/8" drive click-style wrench — a 1/2" drive wrench would be at the bottom of its accurate range.

What is 100 ft-lbs in N·m?

100 ft·lb = 135.58 N·m. This is the most-searched single conversion in the ft-lb-to-Nm space. It's also the typical lug-nut spec for a mid-size US sedan or crossover (Camry, RAV4, Accord, CR-V). Use a 1/2" drive click-style torque wrench, star pattern, two passes.

Do I really need a torque wrench, or can I just snug it down?

For lug nuts, drain plugs, spark plugs, suspension bolts, and anything with a stretch-to-yield design (most modern engine bolts) — yes, you need a torque wrench. The cost of a stripped aluminum head, a snapped wheel stud, or a leaking oil pan is many times the price of a $40 click-style wrench. For a hose clamp, a battery terminal, or a non-structural cosmetic bolt — feel is fine. The line is "does failure damage anything beyond the bolt itself?" — if yes, torque it.

Related tools

• Bolt & Lug-Nut Torque Calculator — when you don't have the spec, calculate it from bolt size + grade + lubrication. Auto-flavored lug-nut tab built in.
• Bar to PSI Converter — same Mike-Reeves treatment for tire pressure: three linked fields (bar / PSI / kPa) with door-jamb sticker decoder.
• Wheel Offset Calculator + Visualizer — see exactly how a wheel swap changes poke and tuck.
• Browse all free tools by Mike Reeves →

Mike's wrench picks for the right ft-lb range

Three wrench-tier categories cover most of what you'll need to actually use the numbers from this converter on your car:

• Best Torque Wrenches — a 1/4" drive in-lb wrench (5 to 60 in-lb), a 3/8" drive click-style (15 to 80 ft·lb), and a 1/2" drive (30 to 250 ft·lb) cover roughly 95% of automotive work. Cheap click wrenches drift fast — calibrate annually or buy a known-good brand. Beam wrenches are accurate forever but slower to use.
• Best Mechanic Tool Sets — a kit with sockets, ratchets, and extensions in 1/4", 3/8", and 1/2" drives is what your torque wrench plugs into. A torque wrench without a 6-point impact-rated socket on a fitting lug nut is asking to round it off.
• Best Impact Wrenches — for breaking lug nuts loose, not for torquing them tight. The procedure is: impact off, click-style on. An impact-only install is the #1 cause of warped rotors and stripped studs at the dealer-service level.

Sources & methodology

• NIST SP 811 — Guide for the Use of the International System of Units — canonical ft·lb ↔ N·m conversion factor (1.3558179483).
• BIPM SI Brochure (9th ed.) — definitions of newton, metre, second.
• Engineering Toolbox — Wheel Bolts Torque — typical lug-nut ranges by stud size.
• Speedway Motors — Wheel Lug Nut Torque Spec Chart — cross-check against vehicle-specific ranges.
• Wrench-class tier ranges (light / general / wheel / heavy / industrial) cross-checked against the sibling torque calculator's severity table — both tools share the same NIST factor and the same wrench classes, so they round-trip cleanly.

The 20+ fixture cases this tool is tested against are in fixtures.json alongside the source. About Mike Reeves · Last reviewed April 29, 2026.

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  Ft-lbs to Nm converter by
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  &middot; Reviewed by Mike Reeves, ASE Master Technician
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