Chain pitch is the center-to-center distance between two consecutive pins in a roller chain. For example, a #40 chain has a nominal pitch of 1/2 inch (12.7 mm). To measure pitch, measure a straight span from pin 1 to pin 11 and divide that distance by 10. Matching pitch is essential, but roller diameter and inner width must also suit the sprocket.
What Is Chain Pitch?
Pitch describes the spacing of the chain joints along its length. It is measured between pin centers, not from the end of one link plate to the other. The same pitch can be written in inches or millimeters: 1 inch equals 25.4 mm.
How to Measure Roller Chain Pitch
Roller chain pitch is the distance between the centers of two adjacent pins. To measure it accurately:
1. Clean and straighten the chain. Lay it flat and apply light tension to remove slack.
2. Measure across several pins. Use a caliper or ruler to measure from the center of the first pin to the center of the sixth pin.
3. Divide by the number of intervals. Six pin centers span five pitch intervals, so divide the measured distance by five.
Pitch = Center-to-center span ÷ Number of pitch intervals
For example, if the distance across five intervals is 63.5 mm, the pitch is 63.5 ÷ 5 = 12.7 mm (1/2 inch).
A worn chain may measure slightly longer than its nominal pitch. Compare your result with a standard chain chart, then check roller diameter and inside width to confirm the chain size.
Formula: average measured pitch = measured span ÷ number of pitch intervals.
Example: a span of 5.000 inches across 10 pitches gives 5.000 ÷ 10 = 0.500 inch. In millimeters, 127.0 ÷ 10 = 12.7 mm. Both readings correspond to a nominal 1/2-inch pitch.
Measuring several pitches reduces the effect of locating the two endpoints imprecisely. It does not remove wear elongation. A used chain may measure longer than its nominal size even when you count and measure correctly.
Chain Pitch Chart: Common ANSI Sizes
The chart below lists nominal pitch for common ANSI sizes in inches and millimeters. It is a pitch reference, not a complete chain identification or load-rating table.
ANSI chain no. | Pitch (in.) | Pitch (mm) |
|---|---|---|
#25 | 1/4 | 6.35 |
#35 | 3/8 | 9.525 |
#40 | 1/2 | 12.7 |
#41 | 1/2 | 12.7 |
#50 | 5/8 | 15.875 |
#60 | 3/4 | 19.05 |
#80 | 1 | 25.4 |
#100 | 1-1/4 | 31.75 |
#120 | 1-1/2 | 38.1 |
#140 | 1-3/4 | 44.45 |
#160 | 2 | 50.8 |
Millimeter values are exact conversions of the nominal inch pitches. Catalogs may round 9.525 mm to 9.53 mm and 15.875 mm to 15.88 mm; these are not different nominal sizes. #40 and lightweight #41 share a pitch but have different chain dimensions.
For roller diameter, inner width and other identification dimensions, see the Roller Chain Size Chart. Check the drawing for the specific replacement chain before ordering.
ANSI vs. British Standard Chain Pitch
British Standard B-series chains also use familiar pitch values. An 08B chain has a 12.7 mm pitch, and a 12B chain has a 19.05 mm pitch. These are the same pitches as ANSI #40 and #60, respectively, but the chains are not automatically interchangeable.
ISO 606 covers both ANSI-derived and European-derived industrial chain series. Calling a chain “metric” does not identify its series. Confirm the complete designation and dimensions instead of choosing a chain solely because the millimeter pitch matches.
What Chain Numbers Tell You About Pitch
For the common ANSI sizes in the chart, the digits before the final digit give the pitch in eighths of an inch. For #40, 4 ÷ 8 = 1/2 inch. For #120, 12 ÷ 8 = 1-1/2 inches. This rule applies to those ANSI designations; do not apply it to every chain numbering system.
Suffixes provide additional information. For example, 60-2 identifies a two-strand chain, while 60H identifies a heavy-series chain. Both retain the nominal 3/4-inch pitch of #60. Strand count and construction still matter when choosing the matching sprocket and connecting link.
Motorcycle Chain Pitch: 520, 525 and 530
Motorcycle chain numbers follow a different convention from industrial ANSI numbers. The common 520, 525 and 530 sizes all have a 5/8-inch (15.875 mm) pitch. The 5 indicates pitch in eighths of an inch; the remaining digits distinguish width designations.
The inner widths differ: published D.I.D specifications list 6.35 mm for 520, 7.93 mm for 525 and 9.53 mm for 530 models. A shared pitch does not make these sizes interchangeable on the same sprockets. Follow the motorcycle manufacturer’s approved chain size, strength specification and sprocket combination. An industrial #50 chain is not a motorcycle replacement recommendation simply because its pitch also measures 5/8 inch.
Why Matching Pitch Alone Is Not Enough
A replacement chain must match the sprocket’s intended chain series and tooth geometry. Wrong-pitch chain can seat poorly, ride up on the teeth or skip. Even with the correct pitch, an unsuitable roller diameter or inner width can prevent proper engagement.
Pitch: the longitudinal spacing between adjacent pin centers.
Roller diameter: the outside diameter of the roller that contacts the sprocket; use the bushing dimension for a rollerless bush chain.
Inner width: the clear distance between the inner link plates, where the sprocket tooth fits.
Strand count: single-, double- or triple-strand chain needs a sprocket made for that arrangement.
Pitch also contributes to drive geometry, but it does not determine allowable working load by itself. Material, construction, speed, lubrication and service conditions affect chain selection. Use the manufacturer’s working-load or power-rating data; tensile breaking strength is not an allowable operating load.
For drive selection and maintenance considerations, see our Industrial Chains and Sprockets guide.
How Wear Affects Chain Pitch Measurements
Wear at the pin-and-bushing joints increases a chain’s measured length under tension. This is commonly called chain stretch, although normal wear elongation is mainly joint wear rather than elastic stretching of the plates. The nominal chain size remains the same.
Wear elongation (%) = [(measured length − nominal length) ÷ nominal length] × 100.
For a nominal 1/2-inch-pitch chain measured over 10 pitches, nominal length is 5.000 inches. A measured length of 5.075 inches gives [(5.075 − 5.000) ÷ 5.000] × 100 = 1.5% elongation. This example demonstrates the calculation; it is not a universal replacement limit.
Follow the chain or equipment manufacturer’s replacement limit. The permitted elongation can vary with sprocket tooth count, drive layout and service requirements. Do not assume that 3% is acceptable for every industrial drive or that every wear gauge uses the same limit. Inspect sprocket condition and use a gauge intended for the chain being checked.
Frequently Asked Questions
Is chain pitch the same as link length?
Only if “link length” means the distance between adjacent pin centers. The overall length of a link plate includes material beyond the pins and is not the pitch.
Can I use a ruler instead of calipers?
A ruler can help identify the approximate nominal pitch if you measure several intervals on a straight, taut chain. It may not resolve small wear differences. For a replacement decision, use the manufacturer’s specified procedure or a suitable chain wear gauge.
Does double-pitch chain have the same pitch as standard chain?
No. Double-pitch chain has twice the pitch of the corresponding standard short-pitch size. For example, C2040 has a 1-inch pitch, compared with the 1/2-inch pitch of #40. Check its specified sprocket compatibility before replacing either chain.
Is chainsaw chain pitch measured the same way?
Chainsaw chain pitch is normally identified by measuring the distance between the centers of three consecutive rivets and dividing by two. That method spans two rivet intervals. Use chainsaw-specific specifications, including gauge and drive-link count, rather than the industrial chain chart above.
Need help identifying an industrial chain? Contact us with its marking, measured pitch, inner width, roller diameter, strand count and a clear photo. Include the operating conditions when requesting a replacement recommendation.
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