Roller chain size chart
Every BS and ANSI size we supply, in millimetres and inches: pitch, roller, width, plate, pin and the standard minimum breaking loads. Click any size for its full page.
Same pitch does not mean same chain: BS and ANSI sizes differ in roller and width. Measure all three identifying dimensions before ordering.
British Standard (ISO 606) roller chain
| Chain | Pitch (in) | Pitch (mm) | Inner width (mm) | Roller Ø (mm) | Plate height (mm) | Pin Ø (mm) | Min breaking load kgf | Weight (kg/m) |
|---|---|---|---|---|---|---|---|---|
| 05B | 8 mm | 8.00 | 3.00 | 5.00 | 7.11 | 2.31 | 449 (4.4 kN) | 0.16 |
| 06B | 3/8″ | 9.525 | 5.72 | 6.35 | 8.26 | 3.28 | 908 (8.9 kN) | 0.39 |
| 08B | 1/2″ | 12.70 | 7.75 | 8.51 | 11.81 | 4.45 | 1,816 (17.8 kN) | 0.65 |
| 10B | 5/8″ | 15.875 | 9.65 | 10.16 | 14.73 | 5.08 | 2,265 (22.2 kN) | 0.92 |
| 12B | 3/4″ | 19.05 | 11.68 | 12.07 | 16.13 | 5.72 | 2,949 (28.9 kN) | 1.24 |
| 16B | 1″ | 25.40 | 17.02 | 15.88 | 21.08 | 8.28 | 6,122 (60.0 kN) | 2.65 |
| 20B | 1¼″ | 31.75 | 19.56 | 19.05 | 26.42 | 10.19 | 9,694 (95.1 kN) | 3.85 |
| 24B | 1½″ | 38.10 | 25.40 | 25.40 | 33.40 | 14.63 | 16,327 (160.1 kN) | 7.60 |
ANSI (ASME B29.1) roller chain
| Chain | Pitch (in) | Pitch (mm) | Inner width (mm) | Roller Ø (mm) | Plate height (mm) | Pin Ø (mm) | Min breaking load kgf | Weight (kg/m) |
|---|---|---|---|---|---|---|---|---|
| 25 | 1/4″ | 6.35 | 3.10 | 3.30 | 6.02 | 2.31 | 357 (3.5 kN) | 0.14 |
| 35 | 3/8″ | 9.525 | 4.68 | 5.08 | 9.05 | 3.60 | 806 (7.9 kN) | 0.33 |
| 40 | 1/2″ | 12.70 | 7.85 | 7.92 | 12.07 | 3.98 | 1,418 (13.9 kN) | 0.63 |
| 50 | 5/8″ | 15.875 | 9.40 | 10.16 | 15.09 | 5.09 | 2,224 (21.8 kN) | 1.01 |
| 60 | 3/4″ | 19.05 | 12.57 | 11.91 | 18.10 | 5.96 | 3,194 (31.3 kN) | 1.44 |
| 80 | 1″ | 25.40 | 15.75 | 15.88 | 24.13 | 7.94 | 5,673 (55.6 kN) | 2.63 |
| 100 | 1¼″ | 31.75 | 18.90 | 19.05 | 30.17 | 9.54 | 8,878 (87.1 kN) | 3.74 |
| 120 | 1½″ | 38.10 | 25.22 | 22.23 | 36.20 | 11.11 | 12,755 (125.1 kN) | 6.18 |
| 140 | 1¾″ | 44.45 | 25.22 | 25.40 | 42.23 | 12.71 | 17,347 (170.1 kN) | 7.49 |
| 160 | 2″ | 50.80 | 31.55 | 28.58 | 48.26 | 14.29 | 22,755 (223.2 kN) | 10.10 |
Breaking loads are the standard minimums (ISO 606 / ASME B29.1), not working loads; see the drive design guide for sizing. Duplex and triplex share the simplex dimensions. Stainless steel, hollow-pin, straight-plate and attachment versions are covered on their own pages.
Straight answers
How do I measure which chain size I have?
Measure three things: the pitch (pin centre to pin centre, measured over several pitches and divided, for accuracy), the roller diameter, and the inner width between the plates. Match them to the chart above; the identification guide shows exactly where to put the callipers.
Are BS and ANSI chains of the same pitch interchangeable?
Not automatically. 08B and ANSI 40 are both 1/2 inch pitch, but roller diameters and widths differ, so the chain may not seat properly on the other standard's sprockets. Check the BS-ANSI cross-reference guide before substituting.
What do the breaking load figures mean?
They are the standard minimum breaking loads from ISO 606 (BS sizes) and ASME B29.1 (ANSI sizes): the load a new chain must withstand in a tensile test, not a working load. Drives are sized with a service factor well below these figures; the drive design guide covers how.
Do duplex and triplex chains have different dimensions?
The pitch, roller diameter and plate dimensions are identical to the simplex chain of the same size; a duplex chain is two rows of the same chain on common pins. Only the overall width and the sprockets change.
Found your size?
Send the designation and the length — we'll quote it cut to your pitch count with the connecting link fitted, same day.