Newton Meter (Torque) Calculator
Calculate torque in newton meters (N·m), or solve for force and lever arm length using the torque equation.
where τ = torque (N·m), F = force (N), r = distance from pivot (m), θ = angle between force and lever arm.
What Is a Newton Meter?
A newton meter (N·m) is the SI unit of torque (also called moment of force). Torque describes how strongly a force causes an object to rotate around a pivot point. In practical terms, if you use a wrench to tighten a bolt, torque is what twists that bolt.
One newton meter is produced when a 1-newton force is applied at a perpendicular distance of 1 meter from the rotation axis.
Torque Formula Explained
Standard Equation
τ = F × r × sin(θ)
- τ: torque in newton meters (N·m)
- F: applied force in newtons (N)
- r: lever arm distance in meters (m)
- θ: angle between force direction and lever arm
If force is perpendicular to the lever arm, θ = 90° and sin(90°) = 1, so the formula simplifies to: τ = F × r.
How to Use This Newton Meter Calculator
1) Choose what you want to solve for
Select Torque, Force, or Distance from the dropdown.
2) Enter known values
Fill in the other fields with known values. Include the angle if the force is not perpendicular.
3) Click Calculate
You will get the solved value and a torque conversion summary (N·m, lb-ft, in-lb, kgf·m).
Quick Unit Conversions for Torque
- 1 N·m = 0.737562 lb-ft
- 1 N·m = 8.850746 in-lb
- 1 N·m = 0.101972 kgf·m
- 1 lb-ft = 1.355818 N·m
Worked Examples
Example 1: Find Torque
A 50 N force is applied 0.3 m from the pivot at 90°.
τ = 50 × 0.3 × sin(90°) = 15 N·m
Example 2: Find Required Force
You need 120 N·m torque using a 0.4 m wrench at 90°.
F = 120 / (0.4 × 1) = 300 N
Example 3: Non-Perpendicular Force
Force is 80 N at 0.5 m with an angle of 30°.
τ = 80 × 0.5 × sin(30°) = 20 N·m
Common Mistakes to Avoid
- Using centimeters instead of meters without converting.
- Forgetting the angle term when force is not perpendicular.
- Using sin(θ) with θ in radians when your input is degrees (or vice versa).
- Confusing torque (N·m) with energy (joule), even though units look similar.
FAQ
Is N·m the same as joule?
Dimensionally yes, but physically they represent different concepts. N·m for torque describes rotational effect; joule describes energy/work.
Can torque be negative?
Yes. The sign indicates direction of rotation (clockwise vs. counterclockwise), depending on your sign convention.
Why does angle matter?
Only the component of force perpendicular to the lever arm causes rotation. That is exactly what the sin(θ) factor captures.
Final Note
Whether you are working on mechanical design, automotive maintenance, robotics, or physics homework, a reliable newton meter calculator helps you compute torque quickly and accurately. Use consistent units, double-check angle assumptions, and you will get dependable results every time.