Chain Size Calculator
Measure your chainstay and count the teeth on your largest chainring and largest rear cog. The calculator gives the chain length in links and how many to take out of a new 116 link chain.
- Chainstay formula
- Links to remove
- Road, gravel and MTB
For derailleur bikes. Full-suspension bikes should be sized with the shock fully compressed, when the chain is longest.
Chain length is measured in links, two to the inch. A bike chain has a pitch of half an inch, so one inch of chain is one inner link and one outer link. Chains must be joined inner to outer, so the length always comes in whole inches, an even number of links.
Typical chain lengths
Common setups and their link counts. Search for your gearing.
| Bike | Chainstay (mm) | Gearing | Links |
|---|---|---|---|
| Road compact | 410 | 50/34, 11-32 | 112 |
| Road race | 405 | 53/39, 11-28 | 110 |
| Endurance road | 415 | 50/34, 11-34 | 112 |
| Gravel 1x | 425 | 42, 10-44 | 110 |
| Gravel 2x | 425 | 46/30, 11-34 | 112 |
| Trail MTB 1x | 435 | 32, 10-52 | 118 |
| XC MTB 1x | 430 | 34, 10-50 | 116 |
| Commuter 1x | 440 | 40, 11-42 | 112 |
Most new chains come with 112 to 126 links. Road chains are often sold at 114 or 116 links, and 12-speed MTB chains at 126.
Chainstay and chain length
Three common setups. Slide the chainstay length.
Bigger cassettes need longer chains, which is why 1x mountain bikes with 50 or 52 tooth cogs use chains of 116 to 126 links.
How to size a chain on the bike
Check the formula with the big-big method. Step through it.
Measure the chainstay
From the centre of the crank axle to the centre of the rear axle.
SRAM Eagle and Shimano 12-speed mountain bike groups have their own sizing guides that use sag position and a chain gauge. Follow the maker's method if it differs.
Too long, right or too short
Small errors cause real problems. Pick a case.
Slaps the frame, drops off over bumps and sags in small ring and small cog.
Smooth shifting across the whole cassette and good derailleur tension.
Pulls the derailleur straight in big-big and can damage the hanger.
A chain one inch too short is dangerous. Shifting into the big ring and big cog can rip off the rear derailleur.
Fitting a new chain
A quick routine for a smooth drivetrain. Tick each step.
Tick each item as you go.
Replace the chain when it has stretched 0.5% for 11 and 12-speed or 0.75% for older drivetrains. Leaving it longer wears out the cassette and chainrings.
What you get
Length and how to get there. Each tile explains one result.
Total links, always an even number.
Half the link count.
The formula before rounding.
From a standard 116 link chain.
How the joiner counts in the total.
Count links by counting rivets. A 116 link chain has 116 pins including the joining link.
Frequently Asked Questions
No question matches that search.
How many links should my bike chain have?
Most road bikes use 108 to 114 links, and 1x mountain bikes 116 to 126. Use the calculator for your exact frame and gears.
How do I calculate bike chain length?
Chain length in inches = 2 × chainstay + front teeth ÷ 4 + rear teeth ÷ 4 + 1. Round up to a whole inch, then double for links.
Can a chain have an odd number of links?
Not with standard links. Use a half link if you need an odd count, which is common on single-speed bikes.
How do I measure chainstay length?
From the centre of the bottom bracket to the centre of the rear axle, in a straight line.
What happens if my chain is too short?
The rear derailleur can be pulled too far in the big ring and big cog, which can damage it or the frame.
Does the quick link count as a link?
Yes. It replaces one outer link, so include it in the total.
How often should I replace my chain?
Every 2,000 to 5,000 km, or when a chain checker shows 0.5% wear on 11 and 12-speed bikes.
Get the chain right first time
Measure the chainstay, count the biggest ring and cog and let the formula give you the link count. Check it on the bike in big-big, cut once and your gears will shift cleanly across the whole range.
More size calculators
Each one has its own calculator, worked examples and answers to common questions.