How to read a bearing code

What the digits and letters in a code like 6205-2RS C3 mean: type, size series, bore, seal and clearance, with short examples.

A bearing code tells you the type, size and features at a glance. Standard codes follow the same rules across brands. Take 6205-2RS C3 as an example:

Part	Meaning
6	Type: single row deep groove ball bearing
2	Size series: sets the outer diameter and width
05	Bore: 05 × 5 = 25 mm
2RS	Rubber seals on both sides
C3	Internal clearance greater than normal

First digit: bearing type

Code	Type	Example
1	Self-aligning ball	1205
2	Spherical roller	22210
3	Tapered roller	30205
5	Thrust ball	51105
6	Deep groove ball	6205
7	Angular contact ball	7205
N, NU, NJ	Cylindrical roller	NU 205

Four-digit codes starting with 3 (such as 3205) are double row angular contact ball bearings.

Last two digits: bore

If the last two digits are 04 or higher, multiply by 5: 25 mm for 6205, 50 mm for 6310. Smaller bores follow a different rule:

Code	Bore
00	10 mm
01	12 mm
02	15 mm
03	17 mm

In three-digit codes the last digit is the bore itself: a 608 bearing has an 8 mm bore.

Middle digit: size series

The bore stays the same; a higher series means a thicker bearing with more load capacity:

Code	Bore × OD × width
6805	25 × 37 × 7 mm
6905	25 × 42 × 9 mm
6005	25 × 47 × 12 mm
6205	25 × 52 × 15 mm
6305	25 × 62 × 17 mm
6405	25 × 80 × 21 mm

Letters at the end

Z, ZZ, RS, 2RS: seal type (2RS vs ZZ)
C2, C3, C4: internal clearance (what C3 means)
K: tapered bore
N, NR: snap ring groove in the outer ring; NR includes the snap ring
M, TN: brass cage (M), polyamide cage (TN)

Brands may write the same bearing differently: SKF 6205-2RSH, FAG 6205-2RSR, NSK 6205DDU and NTN 6205LLU are all the same size with seals on both sides.

If the code is unreadable

Enter the code or the size in the Bearing finder to see equivalents and stock. If the code has worn off, see how to measure a bearing.