Bearing Sizes

Boundary dimensions for 52 deep groove ball bearings across the 6000, 6200 and 6300 series — bore, outside diameter and width in millimetres and inches.

Data verified 2026-09-29 · based on ISO 15:2011

Quick Answer

Deep Groove Ball Bearing Boundary Dimensions (ISO 15)

These are boundary dimensions — the bore, outside diameter and width that ISO 15 fixes so that bearings from different makers are interchangeable. They say nothing about internal geometry, load rating, clearance or precision class, all of which vary by manufacturer and by suffix. A 6205 from one maker and another will fit the same housing and shaft but may have different dynamic capacity, different internal clearance and different limiting speed.

The bore rule is worth memorising: for the last two digits 04 and above, bore = digits × 5 mm. Below 04 the mapping is direct — 00 = 10 mm, 01 = 12 mm, 02 = 15 mm, 03 = 17 mm — which is why a 6200 has a 10 mm bore. The first digit gives the series, and the series sets the outside diameter for a given bore: 6000 is extra light, 6200 light and 6300 medium.

The Three Series and Why Diameter Ratio Matters

The 6000, 6200 and 6300 series are the same bearing family in three section heights. For a 25 mm bore, the 6005 has a 47 mm outside diameter, the 6205 has 52 mm and the 6305 has 62 mm.

The series choice is a trade between load capacity and space. A larger outside diameter at the same bore means bigger balls and a larger pitch circle, so the 6300 series carries substantially more load than the 6200 series, and the 6200 more than the 6000. The heavier series also has a thicker wall, so it tolerates a looser housing fit without deforming the raceway — which matters when the housing material is aluminium or a thin casting.

The ratio columns make this visible. A 6000 series bearing has a D/d ratio near 2.6 and a 6300 near 3.5. Where space is tight, a 6000 series bearing is often chosen even though a 6200 would carry more load, simply because there is no room for the bigger outside diameter.

What the Number Does Not Tell You

Boundary dimensions are only the interchangeable envelope. Everything that decides how the bearing performs is in the suffix and in the manufacturer's catalogue.

Load rating. Two 6205 bearings from different makers have the same boundary dimensions but different dynamic capacity C, because they differ in ball complement, raceway geometry and steel quality. The bearing life calculator needs the actual C from the specific bearing's catalogue, not a generic figure.

Clearance and preload. The suffix tells you the internal clearance class — C2, CN, C3, C4 — and the wrong choice causes either overheating or unacceptable play. C3 is common in electric motors precisely because the fits and the temperature rise would otherwise close the running clearance.

Shields and seals. Z, 2Z, RS, 2RS and their many variants are all the same boundary dimensions but differ in friction, speed limit and contamination protection.

Precision class. ABEC 1 through ABEC 9 (or ISO P0 to P2) grade the running accuracy. A precision-grade 6205 costs several times a standard one and is only needed where runout directly affects the machine's output.

Frequently Asked Questions

How do I read a bearing number?

The first digit is the series — 6 for deep groove ball, then 0, 2 or 3 for extra light, light or medium. The last two digits give the bore: for 04 and above, bore = digits × 5 mm, so a 6205 has a 25 mm bore. Below 04 the mapping is direct: 00 = 10 mm, 01 = 12, 02 = 15, 03 = 17 mm.

What is the difference between the 6000, 6200 and 6300 series?

Section height. For the same bore, 6000 is extra light, 6200 light and 6300 medium — a 25 mm bore gives 47 mm, 52 mm and 62 mm outside diameters respectively. The heavier series carries more load and has a thicker wall, at the cost of a larger envelope.

Are bearings from different manufacturers interchangeable?

They will fit the same housing and shaft if they share boundary dimensions, but they are not otherwise equivalent. Load rating, internal clearance, cage design, limiting speed and sealing all vary. Substituting across brands is usually acceptable for the mechanical fit, but the load rating and the operating temperature must be checked separately.

What does the suffix on a bearing number mean?

It encodes features that are not in the boundary dimensions. 2RS means two rubber seals, ZZ means two metal shields, C3 means increased internal clearance, and N or NR means a snap ring groove. The exact meaning of a suffix is manufacturer-specific, so check the maker's catalogue rather than assuming.

How do I choose the right bearing size?

Start from the shaft diameter, which fixes the bore. Then choose the series from the available housing space and the required load: use the bearing life calculator with the specific bearing's dynamic capacity to check the L10 life. Where space allows, a heavier series is the cheaper way to gain capacity than a larger bore.

Related

• Bearing Life Calculator
• Fits and Tolerances
• ISO 286 Tolerance Chart
• SFM to RPM Calculator
• GD&T Symbols
• AISI 52100 Bearing Steel

Value Sources

Each data column on this page is tied to the source it came from. The numbers in square brackets correspond to the table headers above.

Data Sources

Cross-checked against:

• Bore, outside diameter and width checked against the ISO 15 boundary dimension tables
• The bore rule verified across the series — last two digits × 5 for 04 and above, direct mapping below
• Six bearings held as known-value checks, including a pair with the same bore and different series
• All inch conversions recomputed at build time

Derived values — the following values on this page are calculated, not taken directly from the standard:

Only boundary dimensions are given. Load rating, internal clearance, cage type, sealing, precision class and limiting speed vary by manufacturer and by suffix, and are what decide whether a bearing suits an application. Use the specific manufacturer's catalogue for any of those.

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