Roller Chain Length Calculator
Estimate chain link count for two sprockets and calculate center distance after rounding to an even link count.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Use the standard two-sprocket approximate length in pitches, round upward to an even count and invert the same approximation.
Links≈2C/p+(z1+z2)/2+(z2−z1)²p/(4π²C)
Worked example
For equal 20-tooth sprockets with center distance 50 pitches, the ideal estimate is exactly 120 links.
Assumptions and input details
Approximate pitch-line geometry, no tensioner, wear, sag, chordal motion or load rating. Desired center distance must be at least the larger pitch radius and the inversion must have a real positive solution.
Unit definitions
Unit selection is independent of language. Each selector contains only units for its physical quantity. Calculations use defined base units internally.
Choose from 23 length definitions, including explicitly labelled regional measures. Area conversions square the length factor; geometric volumes cube it.
Regional measures are not interchangeable merely because their names look similar. This is a documented selection, not a claim to include every historical unit.
NIST measurement tables · Japanese traditional units · Mainland China and Hong Kong unit distinctions
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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