Uses ATH in millimeters, largest chainring, largest rear cog and derailleur pulleys.
Quick answer
Returns links plus total length in inches and centimeters.
Useful before installation, maintenance or drivetrain changes.
Which inputs matter
For a practical estimate, the calculator needs the distance between bottom bracket center and rear axle, the largest tooth counts in front and rear, and the derailleur pulleys. That combination creates the longest chain path and is therefore key for minimum length.
- ATH in millimeters, centimeters or inches
- Teeth on the largest chainring
- Teeth on the largest cog or cassette sprocket
- Teeth per pulley when both derailleur pulleys are the same size
How to interpret the result
The result is a calculated starting point. For modern derailleurs, full-suspension bikes, large cassettes or manufacturer-specific setups, compare it with the official installation guide.
Why correct chain length matters
A chain that is too short can damage the derailleur, frame or drivetrain. A chain that is too long can hurt shifting precision and chain tension. The calculator gives you a clear baseline before cutting.
FAQ
Free chain length calculator
Which method does the chain length calculator use?
It uses ATH plus the tooth counts of the largest front chainring, largest rear cog and both derailleur pulleys to estimate a suitable chain length.
Can I use the result directly before cutting a chain?
Use it as a guideline. During installation, still check the requirements from your derailleur, frame and drivetrain manufacturer.
Does the calculator work for 1x and 2x drivetrains?
Yes. Use the largest relevant tooth combination in front and rear.
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