A bearing number is made up of many numbers that represent various characteristics of bearing. A bearing number, in general, contains information on bearing types, bearing series, bore size, and sealing basic designation typically contains three to five digits

The first digit of the bearing refers to the type of bearing.

The second digit identify the bearing series

The last two digits of the basic designation identify the size code of the bearing bore. The size code multiplied by 5 gives the bore diameter (d) in mm.

For instance, let’s take an example 6310.How can we know more about the bearing base on the number.

The first number ‘6’ represents the bearing to be deep groove bearing.

The second digit ‘3’ bearing series which refer to the bearing toughness which is medium

The last two digit represents is the bore size of the bearing.We can get the diameter by multiple five to provide us a clear diameter(d) in mm this is one of the way to identify one of the ball bearing size by looking at the designation code.So what we can tell 6310 inner diameter is 50 mm.In bearing number the last digit or last second digit if it has 5 digits can indicate the bearing size.

The  table will helps to identify types of bearings by number Types of bearing and their code.

Deep Groove Ball Bearing	6
Cylindrical Roller Bearing	N
Tapered Roller Bearing	32/T
Spherical Roller Bearing	2

The  table will helps to identify types of bearings series toughness

Extra Light	0
Extra Light Thrust	1
Light	2
Medium	3
Heavy	4
Extra thin section	8
Very thin section	9

How do we find bearing numbers?

One of the simplest ways to find the bearing number is to look for designation numbers. They are often engraved on the bearing’s surface. However, if they have been employed for a long time, the designation number may be wipe away owing to wear.To know the designation number we can take it’s inner diameter divided by five.