Chain pitch is the distance between links on a chain, measured from pin center to pin center. It’s the single most important measurement for matching a chain to its sprockets, whether you’re replacing a chainsaw chain, sizing an industrial roller chain, or shopping for a bicycle chain. Get the pitch wrong and the chain won’t mesh with the teeth it’s supposed to ride on.
How Pitch Is Measured
The basic idea is simple: pitch is the distance from the center of one pin (or rivet) to the center of the next. In practice, you’ll get a more accurate reading by measuring across several links and dividing. Lay the chain flat, measure from the center of one pin to the center of a pin several links away, then divide by the number of spaces between pins in that span. If you measure 3 inches across 3 link spaces, your pitch is 1 inch.
Chainsaw chains use a slightly different convention. Because the rivets alternate between different link types, the standard method is to measure the distance between any three consecutive rivets, then divide by two. The result is your pitch.
A ruler works for a rough check, but calipers give you precision down to thousandths of an inch, which matters when you’re distinguishing between sizes that are close together.
Chainsaw Chain Pitch Sizes
Chainsaw chains come in six standardized pitch sizes: 1/4″, 1/4″ P (a low-profile variant), 3/8″ P (also low-profile), .325″, 3/8″, and .404″. The smaller pitches like 1/4″ and 3/8″ P are found on lighter homeowner saws, while .325″, 3/8″, and .404″ are used on mid-range to professional-grade machines.
Your saw’s guide bar typically has the correct pitch, gauge (the thickness of the drive links), and bar length printed or stamped on it. All three specs need to match the replacement chain exactly. A chain with the wrong pitch won’t sit properly on the bar’s sprocket nose or the drive sprocket at the powerhead, which creates a safety hazard and damages the equipment.
ANSI Roller Chain Numbering
Industrial roller chains used in conveyors, machinery, and power transmission follow the ANSI (American National Standards Institute) numbering system. The chain number itself tells you the pitch. The first one or two digits represent the pitch in eighths of an inch. A No. 40 chain has a pitch of 4/8″, or 0.500 inches. A No. 80 chain has a pitch of 8/8″, or exactly 1 inch.
Here are the most common ANSI chain sizes and their pitches:
- No. 25: 0.250″ pitch
- No. 35: 0.375″ pitch
- No. 40: 0.500″ pitch
- No. 50: 0.625″ pitch
- No. 60: 0.750″ pitch
- No. 80: 1.000″ pitch
- No. 100: 1.250″ pitch
- No. 120: 1.500″ pitch
- No. 160: 2.000″ pitch
- No. 240: 3.000″ pitch
The last digit in the ANSI number indicates the chain type. A 0 means a standard roller chain, a 1 means a lightweight chain with the same pitch but narrower rollers, and a 5 means a rollerless bushing chain. So a No. 40 and a No. 41 share the same 0.500″ pitch but differ in construction and load capacity.
Bicycle Chain Pitch
Virtually every modern bicycle chain uses a universal half-inch pitch (0.500″), measured rivet to rivet. This has been the standard for decades, and all bicycle sprockets are cut to match it. So when you’re buying a replacement bike chain, pitch is not the variable you need to worry about.
What does vary is the chain’s width, which must match the number of rear cogs on your drivetrain. More cogs means tighter spacing, which means a narrower chain. A bike with 6, 7, or 8 rear cogs uses a chain roughly 7 mm wide across the rivets. A 10-speed setup uses about 6 mm, an 11-speed about 5.5 mm, and a 12-speed about 5.3 mm. Single-speed bikes use a wider 1/8″ roller chain that isn’t interchangeable with derailleur chains. Using the wrong width won’t cause the chain to skip off the sprocket the way a wrong pitch would, but it can lead to poor shifting, extra noise, and accelerated wear.
Why Pitch Matters for Replacement
A chain and its sprockets are designed as a matched system. The teeth on a sprocket are spaced to receive links at a specific pitch. If you install a chain with a slightly different pitch, the pins won’t land in the tooth valleys correctly. On a chainsaw, this means the chain can jump or bind. On industrial equipment, it accelerates wear on both the chain and the sprocket and can cause the chain to climb off under load.
When a chain stretches over time, what’s actually happening is that the pins and bushings inside each link are wearing down, effectively increasing the pitch. A chain that started at exactly 0.500″ per link might measure 0.510″ after thousands of miles or hours of use. That small change is enough to cause skipping on sprocket teeth. This is why mechanics and machinists measure pitch on a worn chain to determine whether it needs replacement, not just whether it “looks” worn.
If you’re replacing a chain and don’t have the original specs, measuring pitch on the old chain (or on the sprocket teeth) is the fastest way to identify what you need. Count the teeth on the sprocket, measure its diameter, or simply measure pin-to-pin distance on the old chain with calipers, and you’ll have the number that matters most.