How do I convert N·m to lb·ft?

Multiply N·m by 0.7376 to get lb·ft. For example, 100 N·m × 0.7376 = 73.76 lb·ft. To convert lb·ft to N·m, multiply by 1.3558.

How do I calculate torque from force?

Torque = Force × Distance. Apply force perpendicular to the lever arm at the measured distance from the pivot. For example, 50 N at 0.3 m = 15 N·m.

What's the relationship between torque and power?

Power = Torque × Angular Velocity. In practical units: Power (kW) = Torque (N·m) × RPM / 9549, or HP = Torque (lb·ft) × RPM / 5252.

Why does a longer wrench create more torque?

Torque = Force × Distance. A longer wrench increases the distance (lever arm), so the same force creates more torque. This is the principle of mechanical advantage.

What torque should I use for bolts?

Bolt torque depends on size, grade, and lubrication. Common examples: M8 Grade 8.8 = 25 N·m, M10 = 50 N·m, M12 = 85 N·m. Always check manufacturer specifications.

What is the difference between torque and force?

Force causes linear motion (pushing/pulling). Torque causes rotational motion (twisting). Torque depends on both the force magnitude and the distance from the rotation axis.

Torque Calculator

Our torque calculator helps engineers, mechanics, and DIYers calculate rotational force. Compute torque from force and distance, convert between N·m, lb·ft, kg·cm and other units, or calculate power output from torque and rotational speed.

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calendar_today Updated: July 2025

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Force

Distance (Lever Arm)

Torque

50 N·m

Unit Conversions

N·m

50.00

lb·ft

36.88

kg·cm

509.86

lb·in

442.55

Formula

τ = F × r = 100 N × 0.5 m = 50 N·m

Input Values

Calculate

rotate_right Torque from Force

fitness_center Force from Torque

bolt Power from Torque & RPM

swap_horiz Convert Torque Units

Torque

N·m

swap_horiz Unit Conversions

1 N·m 0.7376 lb·ft

1 lb·ft 1.3558 N·m

1 N·m 10.2 kg·cm

build Common Bolt Torques

M8 (Grade 8.8) 25 N·m

M10 50 N·m

M12 85 N·m

How to Use This Calculator

Select Mode

Choose to calculate torque, force, power, or convert units

Enter Values

Input the known values (force, distance, torque, RPM)

View Results

See calculated result with unit conversions

The Formula

Torque is the rotational equivalent of linear force. It equals force times the perpendicular distance from the axis of rotation. Power relates to torque by: P = τ × ω (where ω is angular velocity in rad/s).

τ = F × r

lightbulb Variables Explained

τ Torque (rotational force)
F Force applied perpendicular to lever arm
r Distance from pivot point (lever arm)

tips_and_updates Pro Tips

1 N·m = 0.7376 lb·ft = 10.197 kg·cm

Engine torque specs are typically in N·m or lb·ft

Bolt torque specs ensure proper clamping force

Power (kW) = Torque (N·m) × RPM / 9549

Longer wrench = more torque with same force

Always use a torque wrench for critical fasteners

Torque in Physics and Mechanical Engineering

Torque, also called the moment of force, is the rotational equivalent of linear force — it measures how effectively a force causes an object to rotate around an axis. Calculated as force multiplied by the perpendicular distance from the axis of rotation (the moment arm), torque is expressed in Newton-meters (N·m) in the SI system or pound-feet (lb·ft) in imperial units. A longer wrench produces more torque with the same applied force, which is why mechanics use breaker bars for stubborn bolts. In automotive engineering, engine torque determines acceleration and towing capacity — a typical passenger car produces 200-300 N·m, while heavy-duty diesel trucks can exceed 1,500 N·m. Fastener torque specifications are critical for safety: under-torqued bolts can loosen under vibration, while over-torqued bolts risk thread stripping or fatigue failure. The torque-angle relationship follows the formula tau = r × F × sin(theta), where theta is the angle between the force vector and the moment arm. In many applications, converting between N·m and lb·ft is a daily necessity (1 N·m = 0.7376 lb·ft). Understanding torque is fundamental for automotive mechanics, structural engineers, roboticists, and anyone working with rotating machinery.

Understanding Torque

Torque is rotational force measured in N·m or lb·ft. It's crucial for fasteners, engines, and mechanical systems. Higher torque means more rotational force.

Torque Unit Conversion

Common conversions: 1 N·m = 0.7376 lb·ft = 10.197 kg·cm = 8.851 lb·in. Engine specs often use N·m (metric) or lb·ft (imperial).

Frequently Asked Questions

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