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Belt Length Calculator

Estimate open-belt length for two pulleys from diameters and centre distance.

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Interactive calculation

Enter your values

Calculated result

This is a general planning estimate. Check units and verify critical results independently.

Why this result needs checking

Engineering results depend on inputs, assumptions and real-world conditions. Use this as a planning/checking value and verify critical work against manufacturer data, drawings or applicable standards. How our calculations work →

How to use it

Use consistent units and realistic inputs.

Estimate open-belt length for two pulleys from diameters and centre distance. Enter the requested values, calculate the result, then compare it with drawings, catalogues, standards or manufacturer information relevant to the job.

Common mistakes

  • Using radius instead of diameter
  • Applying the open-belt formula to crossed belts
  • Ignoring tensioner travel and manufacturer belt increments

Frequently asked questions

What does this calculator calculate?

Estimate open-belt length for two pulleys from diameters and centre distance.

Is the answer exact?

No. The formula provides an engineering estimate based on the inputs and assumptions shown. Real systems can include tolerances, friction, losses, material variation and regulatory requirements.

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