How to Measure Chain with Calipers
When you are trying to identify a roller chain, the most important measurement is the chain pitch. Pitch is the distance from the center of one pin to the center of the next pin. If the pitch is wrong, the chain will not properly match the sprocket.
That is why using calipers is one of the best ways to measure roller chain. A tape measure or ruler can get you close, but calipers give you a cleaner, more accurate measurement, especially on smaller chain sizes.
Most important measurement: Roller chain pitch is measured from the center of one pin to the center of the next pin. This is usually the fastest way to identify your chain size.
Why Chain Pitch Matters Most
Roller chain pitch determines which sprockets the chain can run on. A chain may look close to the right size, but if the pitch does not match the sprocket, the chain can ride incorrectly, wear faster, skip teeth, or damage the drive system.
For example, a chain with a 1/2″ pitch is commonly ANSI #40 roller chain, as shown below. That small difference matters when the chain is running under load.
How to Measure Roller Chain Pitch with Calipers
To measure roller chain pitch with calipers, place one caliper jaw on the center of one chain pin and the other jaw on the center of the next pin. The measurement between those two pin centers is the pitch.
- Lay the roller chain flat on a table.
- Clean off dirt or grease so the pins are easy to see.
- Open the calipers and place each jaw at the center of two neighboring pins.
- Read the center-to-center measurement.
- Compare that measurement to a roller chain size chart.
Accuracy tip: If the chain is worn or stretched, measure across several links and divide by the number of pitches measured. This can give you a more reliable pitch measurement than checking only one link.
Example: Measuring a 1/2″ Pitch Roller Chain
If your calipers read about 0.50″ from the center of one pin to the center of the next pin, the chain has a 1/2″ pitch. That commonly points to #40 roller chain.
After you find the pitch, you should still confirm the roller width, roller diameter, plate height, and plate thickness before ordering. Pitch is the best place to start, but the other dimensions help confirm the exact chain size.
Other Ways to Measure Roller Chain Pitch
Calipers are the best option, but there are a few other ways to estimate roller chain pitch if calipers are not available.
Using a Ruler
A ruler can work for larger chain sizes, but it is harder to line up perfectly with the center of the pins. This method is better for a rough estimate than a final measurement.
Using a Tape Measure
A tape measure can be helpful for measuring across several links. For example, measure from the center of one pin to the center of a pin several spaces away, then divide by the number of pitches. This can help reduce error on worn chain.
Checking the Side Plate
Many roller chains have the chain size stamped on the side plate. Before measuring, clean the chain and check for markings like #40, #50, #60, or #80. If the stamp is worn off or missing, measuring the pitch is the next best step.
Common Roller Chain Pitch Examples
| Common Chain Size | Pitch |
|---|---|
| #25 Roller Chain | 1/4″ |
| #35 Roller Chain | 3/8″ |
| #40 Roller Chain | 1/2″ |
| #41 Roller Chain | 1/2″ |
| #50 Roller Chain | 5/8″ |
| #60 Roller Chain | 3/4″ |
| #80 Roller Chain | 1″ |
| #100 Roller Chain | 1-1/4″ |
| #120 Roller Chain | 1-1/2″ |
| #140 Roller Chain | 1-3/4″ |
| #160 Roller Chain | 2″ |
| #180 Roller Chain | 2-1/4″ |
| #200 Roller Chain | 2-1/2″ |
| #240 Roller Chain | 3″ |
Shop Roller Chain Online
At MDS of Michigan, we sell roller chain, connecting links, offset links, sprockets, and other power transmission parts. If you are not sure what chain size you have, measure the pitch first, then compare it to a roller chain size chart.
Need Help Matching Roller Chain?
Shop roller chain online with MDS of Michigan or send us your measurements for help finding the correct chain size.
