Bike Chain Length Calculator
Geometry estimate and physical verification
Size a replacement bicycle chain
Result
Calculation summary
Enter values to see the result
Live chain-path preview
Large–large geometry sets the baseline
Recommended links
108
Chain length
54 in
Links to remove
8
The formula is rounded upward to an even number of half-inch links, then the selected allowance is added.
How to use this calculator
- 1Measure chainstay length and enter the largest front and rear tooth counts.
- 2For full suspension, add measured maximum chainstay growth.
- 3Choose an allowance, compare package length and verify physically before cutting.
Formula
L(in) = 2C + F/4 + R/4 + 1
The conventional formula is converted to half-inch links and rounded upward to an even count.
Calculation steps
- Convert chainstay and suspension growth to inches.
- Calculate raw large–large length and round safely.
- Add allowance and compare with the packaged link count.
Worked example
A 430 mm chainstay with a 50-tooth ring and 34-tooth sprocket yields about 108 half-inch links before optional allowance.
Assumptions
- A conventional half-inch-pitch bicycle chain is used.
- Largest gears define the formula baseline.
- The package count uses half-inch links.
- Final physical verification is mandatory.
Sources
Frequently asked questions
What does one link mean here?
The result counts each half-inch inner or outer link, matching common package labels such as 116 links.
Why must the count be even?
A standard chain joins compatible inner and outer ends as complete one-inch pairs.
Should I add links for a large cassette?
Follow the exact drivetrain manufacturer's method; the optional allowance makes that choice explicit.
Can I use the formula for full suspension?
Only after accounting for growth and physically checking the chain through suspension travel.