engineering

Belt Drive Calculator

Calculate belt length, speed ratio, belt tensions, and required belt width for V-belt and flat-belt drives

Belt Drive Calculator

Calculate belt length, speed ratio, angle of wrap, and belt tensions for open belt drive systems.

Formulas

L = 2C + π(D₁+D₂)/2 + (D₁−D₂)²/(4C)
i = D₁/D₂   n₂ = n₁/i
F₁/F₂ = e^(μθ)   F_eff = P/v = F₁ − F₂

Flat rubber: 0.3–0.5 | V-belt: 0.5–0.7

Belt Geometry

Belt Length L

2.3139 m

Speed Ratio i

2.0000

Wrap Angle (small pulley)

169.24°

= 2.9538 rad

Driven Speed n₂

750.0 RPM

Belt Speed v

23.562 m/s

Belt Tensions

Tight Side F₁

361.0 N

Slack Side F₂

148.8 N

Effective F_e = F₁−F₂

212.2 N

Design Rule: Center Distance

Recommended: (D₁+D₂)/2 ≤ C ≤ 3(D₁+D₂)
Wrap angle ≥ 120° recommended for smaller pulley

How to Use This Calculator

1

Enter your input values

Fill in all required input fields for the Belt Drive Calculator. Most fields include unit selectors so you can work in your preferred unit system.

2

Review your inputs

Double-check that all values are correct and that you have selected the right units for each field. Incorrect units are the most common source of calculation errors.

3

Read the results

The Belt Drive Calculator instantly computes the output and displays results with units. All calculations happen in your browser — no loading time and no data sent to a server.

Formula Reference

Belt Drive Calculator Formula

See calculator inputs for the governing equation

Variables: All variables and their units are labeled in the calculator interface above.

When to Use This Calculator

  • Use the Belt Drive Calculator when solving homework or exam problems that require quick numerical verification of your hand calculations.
  • Use it during the design phase to rapidly iterate on parameters before running detailed finite element simulations.
  • Use it when reviewing a colleague's calculation or checking a vendor's data sheet for plausibility.
  • Use it to generate reference data for a technical report or presentation without manual computation.

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