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Torque Converter ft-lb to Nm

1 ft-lb = 1.355818 Nm

Example: M8 standard metric bolt torque limit is roughly 25 Nm (18.4 ft-lb) for standard steel Grade 8.8.

Convert torque ratings between foot-pounds and Newton-meters. Select standard bolt sizes and steel classes to see installation limits. Essential for automotive, aerospace, and mechanical engineering applications.

Interactive Torque Converter

Standard Metric Bolt Torque Specifications

Bolt Size Thread Pitch (mm) Class 8.8 Strength Max Torque Class 10.9 Strength Max Torque
M6 1.00 mm 10 Nm / 7.4 ft-lb 14 Nm / 10.3 ft-lb
M8 1.25 mm 25 Nm / 18.4 ft-lb 35 Nm / 25.8 ft-lb
M10 1.50 mm 49 Nm / 36.1 ft-lb 69 Nm / 50.9 ft-lb
M12 1.75 mm 85 Nm / 62.7 ft-lb 120 Nm / 88.5 ft-lb
M14 2.00 mm 135 Nm / 99.6 ft-lb 190 Nm / 140.1 ft-lb
M16 2.00 mm 210 Nm / 154.9 ft-lb 295 Nm / 217.6 ft-lb
Open Bolt Torque Calculator

Understanding Torque Units

Foot-pounds (ft-lb) is the imperial unit of torque, representing the rotational force applied when one pound of force acts at the end of a one-foot lever arm. Newton-meters (Nm) is the SI metric equivalent, where one Newton of force acts at the end of a one-meter arm.

Quick Conversion: Nm = ft-lb × 1.356
Reverse: ft-lb = Nm × 0.7376
Common Values: 10 ft-lb = 13.6 Nm | 50 ft-lb = 67.8 Nm | 100 ft-lb = 135.6 Nm

Torque Wrench Best Practices

Always calibrate torque wrenches annually or every 5,000 cycles. Apply torque in a smooth, steady motion — never jerk or impact. For critical joints, use the "torque-angle" method: tighten to a seating torque, then rotate through a specified angle for precise clamping load.

When converting between ft-lb and Nm for wrench settings, always round to the nearest marked increment on your wrench. Most click-type torque wrenches have accuracy within ±4% of the set value.

Frequently Asked Questions — Torque Conversion

How do you convert ft-lb to Nm?
Multiply the foot-pounds value by 1.355818 to calculate Newton-meters. Formula: Nm = ft-lb × 1.355818. For quick estimates, multiply by 1.356. Example: 25 ft-lb × 1.356 = 33.9 Nm.
What is 20 ft-lb in Nm?
20 ft-lb is equivalent to approximately 27.12 Newton-meters. This torque level is typical for medium-duty fasteners like M8 bolts in automotive applications.
What torque should I use for M8 bolts?
M8 bolts (1.25mm pitch) require 25 Nm (18.4 ft-lb) for Class 8.8 steel and 35 Nm (25.8 ft-lb) for Class 10.9 high-strength steel. Always use a calibrated torque wrench for critical joints.
What is the difference between torque and moment?
Torque is a rotational force that causes angular acceleration, measured in ft-lb or Nm. Moment is a static tendency to rotate about a point. In engineering, the terms are often used interchangeably, but torque specifically implies motion while moment implies potential rotation.
Why is torque specification important for bolts?
Proper bolt torque ensures correct clamping force without over-stretching the bolt. Under-torqued bolts can loosen under vibration, while over-torqued bolts can strip threads, snap the bolt head, or cause fatigue failure. Always follow manufacturer specifications for safety-critical assemblies.

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