Stepper Motor Torque Calculator
Required stepper torque from axis force, screw lead and efficiency — sized with a safety factor and a NEMA class suggestion.
Holding torque on the datasheet is at STANDSTILL — at 600 RPM a typical NEMA 17 delivers barely a third of it, and supply voltage (not current) sets how fast torque falls off. That is why CNC builds run 24–48 V drivers on “12 V” motors. Non-backdrivable ACME screws hold a vertical axis when powered off; ballscrews fall and need a brake.
Stepper Torque Calculator computes the stepper torque your axis needs, from force, screw lead and efficiency — free, instant and private in your browser. CNC, 3D-printer and automation builders choosing motors that never lose steps use it to skip the datasheet algebra: type your numbers, read the answer with the substituted formula shown step by step, and share an exact permalink of the calculation.
About Stepper Motor Torque Calculator
Stepper Torque Calculator computes the stepper torque your axis needs, from force, screw lead and efficiency using the standard engineering relation: T = F·p/(2π·η) + preload, then × safety factor (≥2 — torque collapses with speed). Worked live: 200 N through an 8 mm ballscrew (η 0.9) needs 0.33 N·m — size a 0.65 N·m NEMA 17/23. The result recalculates on every keystroke, the worked-example panel shows your numbers substituted into the formula, and the Copy permalink button encodes the inputs in the URL so a colleague opens exactly your calculation. Everything runs client-side — nothing you type leaves your device.
How to use Stepper Motor Torque Calculator
- 1Enter your values — the tool starts with realistic defaults for this exact use case, so the worked example is meaningful immediately.
- 2Read the live result and the worked-example panel, which substitutes your numbers into the formula step by step.
- 3Adjust any input to compare scenarios, then use Copy result or Copy permalink to share the calculation.
Why use Stepper Motor Torque Calculator?
- ✓Implements the real formula — T = F·p/(2π·η) + preload, then × safety factor (≥2 — torque collapses with speed) — with the substitution shown, not a black box
- ✓Built for CNC, 3D-printer and automation builders choosing motors that never lose steps
- ✓Copy result and permalink buttons — share the exact calculation in a README, forum answer or design review
- ✓100% free, no sign-up, runs entirely in your browser (works offline once loaded)
Frequently asked questions
How do you calculate stepper torque?+
The stepper torque your axis needs, from force, screw lead and efficiency follows T = F·p/(2π·η) + preload, then × safety factor (≥2 — torque collapses with speed). For example, 200 N through an 8 mm ballscrew (η 0.9) needs 0.33 N·m — size a 0.65 N·m NEMA 17/23. The calculator applies the same relation and shows the substituted arithmetic so you can verify every step.
Why size at twice the calculated torque?+
Datasheet holding torque is at standstill; at speed the winding inductance starves current and torque falls — often to a third by 600 RPM. Acceleration, resonance dips and binding eat the rest. 2× at the working speed is the practical floor for never-miss-a-step motion.
Will a vertical axis fall when power is off?+
With a ballscrew (η ≈ 0.9), yes — it back-drives. ACME/trapezoidal screws below ~50 % efficiency self-lock and hold position unpowered, which is why budget Z axes use them despite the friction. Otherwise add a brake or counterweight.
Is the Stepper Torque Calculator free and private?+
Yes — completely free with no sign-up or usage limits, and it runs entirely in your browser: the values you enter are never uploaded or stored on a server.
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