Roller Chain Size Chart
Measure the pitch, roller diameter and inner width of a chain and identify its ANSI number (25 to 240), with the full dimension chart in inches and millimetres.
Measuring across 10 pitches (11 pins) averages out error: 5 in over 10 pitches is a 1/2 in pitch. The result updates as you type.
Measured pitch 12.70 mm (0.500 in)
ANSI 40 or 41 — 1/2 in pitch
Both share a 1/2 in pitch. Measure the inner width between the inner plates: 40 is 7.95 mm (5/16 in), 41 is 6.38 mm (1/4 in).
Roller chain size chart (single strand)
| ANSI | Pitch | Roller Ø | Inner width | Pin Ø | Plate thick. | Min. tensile (ISO 606) | Mass |
|---|---|---|---|---|---|---|---|
| #25 | 1/4″ · 6.350 mm | 3.30 mm · 0.130″ | 3.18 mm · 0.125″ | 2.31 mm | 0.74 mm | 3.6 kN | 0.14 kg/m |
| #35 | 3/8″ · 9.525 mm | 5.08 mm · 0.200″ | 4.78 mm · 0.188″ | 3.59 mm | 1.25 mm | 8.7 kN | 0.33 kg/m |
| #40 | 1/2″ · 12.700 mm | 7.92 mm · 0.312″ | 7.95 mm · 0.313″ | 3.97 mm | 1.50 mm | 15.2 kN | 0.64 kg/m |
| #41 | 1/2″ · 12.700 mm | 7.77 mm · 0.306″ | 6.38 mm · 0.251″ | 3.59 mm | 1.25 mm | 7.4 kN | 0.41 kg/m |
| #50 | 5/8″ · 15.875 mm | 10.16 mm · 0.400″ | 9.53 mm · 0.375″ | 5.09 mm | 2.00 mm | 24.0 kN | 1.04 kg/m |
| #60 | 3/4″ · 19.050 mm | 11.91 mm · 0.469″ | 12.70 mm · 0.500″ | 5.96 mm | 2.40 mm | 34.2 kN | 1.53 kg/m |
| #80 | 1″ · 25.400 mm | 15.88 mm · 0.625″ | 15.88 mm · 0.625″ | 7.94 mm | 3.20 mm | 61.2 kN | 2.66 kg/m |
| #100 | 1 1/4″ · 31.750 mm | 19.05 mm · 0.750″ | 19.05 mm · 0.750″ | 9.54 mm | 4.00 mm | 95.4 kN | 3.99 kg/m |
| #120 | 1 1/2″ · 38.100 mm | 22.23 mm · 0.875″ | 25.40 mm · 1.000″ | 11.11 mm | 4.80 mm | 137.1 kN | 5.93 kg/m |
| #140 | 1 3/4″ · 44.450 mm | 25.40 mm · 1.000″ | 25.40 mm · 1.000″ | 12.71 mm | 5.60 mm | 185.9 kN | 7.49 kg/m |
| #160 | 2″ · 50.800 mm | 28.58 mm · 1.125″ | 31.75 mm · 1.250″ | 14.29 mm | 6.40 mm | 244.6 kN | 10.10 kg/m |
| #180 | 2 1/4″ · 57.150 mm | 35.71 mm · 1.406″ | 35.72 mm · 1.406″ | 17.46 mm | 7.15 mm | 308.2 kN | 13.45 kg/m |
| #200 | 2 1/2″ · 63.500 mm | 39.68 mm · 1.562″ | 38.10 mm · 1.500″ | 19.85 mm | 8.00 mm | 381.7 kN | 16.49 kg/m |
| #240 | 3″ · 76.200 mm | 47.63 mm · 1.875″ | 47.63 mm · 1.875″ | 23.81 mm | 9.50 mm | 550.4 kN | 24.50 kg/m |
What this page cannot tell you
What load the chain can safely carry. Minimum tensile strength is a breaking figure, not a working load; working loads depend on speed, sprockets, lubrication and service factors in the maker’s selection guide. Worn chain measures longer than new. Metric (ISO/BS) and motorcycle chains are not covered.
How to measure roller chain size
- Measure the pitch. Measure from the centre of one pin to the centre of another several links away — 10 pitches (11 pins) is easy to divide.
- Enter the length and the number of pitches. The page divides one by the other to get the pitch.
- Add the roller diameter. Optional: calipers across a roller help confirm the size.
- Add the inner width. Optional: the gap between the inner plates separates chains that share a pitch, such as 40 and 41.
- Read the ANSI number. The match appears at the top and is highlighted in the chart.
10 situations where a chain size chart helps
Replacing a worn chain
An unmarked chain on a machine can be identified from a tape-measure reading.
Buying sprockets
Sprockets are sold by chain number; the chain's size sets the sprocket you need.
Go-karts and mini bikes
Most use #35, #40 or #41; the pitch and width tell them apart.
Telling #40 from #41
Both are 1/2 in pitch; #41 is narrower and lighter. The inner width settles it.
Farm and conveyor equipment
Larger drives use #60 to #120; the chart lists their dimensions and weight.
Ordering by length
Pitch × number of links gives the chain length to order.
Comparing chain strength
The chart lists the ISO 606 minimum tensile strength for each size.
Estimating weight for shipping
Mass per metre is listed for each size.
Checking a parts listing
Compare a listing's dimensions with the standard for that number.
Learning chain numbering
The leading digits of the ANSI number give the pitch in eighths of an inch.
Where the dimensions come from
The chart is Tsubaki Europe's published single-strand table for its ANSI G8 standard roller chain, read on the date shown on the result: pitch, roller diameter, inner width, pin diameter, link plate thickness and height, ISO 606 minimum tensile strength and approximate mass, for sizes #25 to #240. Values are in millimetres as printed; inch figures are conversions at 25.4 mm per inch. Two Tsubaki-specific sizes in that table (RS37 and RS38) are left out; #41 is the standard light-duty ANSI size.
The page divides the length you measure by the number of pitches it spans to get the pitch, picks the ANSI size with the nearest pitch, and — where two sizes share a pitch — uses the roller diameter and inner width to rank them. A measured pitch more than 5% from every listed size is reported as no match.
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Limits: the table is one manufacturer's figures for ANSI standard chain; other makers' dimensions can differ slightly, and heavy, double-pitch, metric (ISO/BS) and motorcycle chains are not covered. Worn chain measures longer than new. Tensile strength is a minimum breaking load, not a working load — selecting a chain for a drive needs the maker's selection procedure.
Sources
- Tsubaki Europe — ANSI G8 standard roller chain — Single-strand dimension and strength tables
Frequently asked questions
How do I tell what size roller chain I have?
Measure the pitch — the distance between pin centres. 1/4 in is #25, 3/8 in #35, 1/2 in #40 or #41, 5/8 in #50, 3/4 in #60 and 1 in #80.
What is the difference between #40 and #41 chain?
Both have a 1/2 in pitch. In Tsubaki's table #40 has a 7.95 mm inner width and 7.92 mm rollers; #41 has a 6.38 mm inner width and 7.77 mm rollers and is lighter.
What does the chain number mean?
The digits before the last give the pitch in eighths of an inch: #40 is 4/8 = 1/2 in, #80 is 8/8 = 1 in.
What is the pitch of #35 chain?
3/8 in (9.525 mm), with a 5.08 mm roller and 4.78 mm inner width.
Why measure over 10 links?
Small errors average out. 10 pitches of #40 chain measure 5 in.
Does this cover motorcycle chain like 420 or 530?
No. Motorcycle chains share pitches with ANSI sizes but have their own widths; this chart covers ANSI standard chain only.
How strong is #40 chain?
Tsubaki lists a 15.2 kN minimum tensile strength to ISO 606 for single-strand RS40. That is a breaking figure, not a working load.
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