# 623 bearing dimensions

A 623 bearing is 3 mm bore × 10 mm outside diameter × 4 mm wide (0.118 × 0.394 × 0.157 in). The sealed version is 623-2RS; the shielded version is 623-ZZ.

## 623 data

- Type: deep groove ball bearing, 62 series (light)
- Bore d: 3 mm (0.1181 in)
- Outside diameter D: 10 mm (0.3937 in)
- Width B: 4 mm (0.1575 in)
- Bore code: Under 10 mm bore the last digit is the bore itself: 3 = 3 mm
- Sealed: 623-2RS; shielded: 623-ZZ; open: 623

## Designations by maker

| Maker | Sealed | Shielded |
|---|---|---|
| SKF | 623-2RSH | 623-2Z |
| FAG (Schaeffler) | 623-2RSR | 623-2ZR |
| NSK | 623DDU | 623ZZ |
| NTN | 623LLU | 623ZZ |
| Koyo (JTEKT) | 623-2RS | 623ZZ |
| Timken | 623-2RS | see catalogue |


Load ratings and speed limits vary by maker: take them from the manufacturer's catalogue.

## FAQ

**What size is a 623 bearing?**
3 mm bore, 10 mm outside diameter and 4 mm wide, which is 0.118 × 0.394 × 0.157 in.

**What does 2RS mean on a 623 bearing?**
623-2RS has rubber contact seals on both sides. 623-ZZ (also written 623-2Z) has metal shields on both sides. Both have the same 3 × 10 × 4 mm dimensions.

**Is 623-2RS the same as 623-ZZ?**
They are the same size and interchangeable in a housing. The sealed 623-2RS keeps out fine dirt and water better; the shielded 623-ZZ runs with less friction.

**What is the SKF equivalent of 623-2RS?**
SKF writes it 623-2RSH; FAG 623-2RSR, NSK 623DDU, NTN 623LLU and Koyo 623-2RS. Check the maker's catalogue for the exact seal type.

**What does the number 623 mean?**
6 is the deep groove ball bearing type, 2 is the light dimension series, and under 10 mm bore the last digit is the bore itself: 3 = 3 mm.

Source page: https://machinistcharts.com/bearing/623/
Updated: 2026-10-06
Publisher: MachinistCharts (https://machinistcharts.com)