Technical Resource · Reference Only
O-Ring Size Charts by Standard
Complete dimensional reference tables for every O-ring sizing standard FITCO manufactures to — AS568, Metric, JIS B 2401, BS 4518, GB/T 3452.1 and JASO F404. Each page lists full ID, cross-section and tolerance data in millimetres and inches.
Standards
Browse by standard
AS568 (Inch / Dash Number)
Full A-series dash-number range, -001 through -906+ and boss-seal series, with nominal, standard O-ring and metric-equivalent dimensions.
View full chart →Metric
Complete metric O-ring range from 1mm to 690mm ID across cross-sections 1.00mm–6.00mm.
View full chart →JIS B 2401 (Japan)
P-series (dynamic/static), G-series (static), S-series (small) and V-series (very large) O-rings to the Japanese Industrial Standard.
View full chart →BS 4518 (British Standard)
Full BS 4518 dimensional range across all standard cross-sections.
View full chart →GB/T 3452.1 (China)
Complete GB/T 3452.1 Chinese national standard O-ring dimensions.
View full chart →JASO F404 (Japan Automotive)
JASO F404 automotive O-ring series across the 1000, 2000 and 3000 size ranges.
View full chart →ISO 3601 (Metric / International)
Full ISO 3601-1 metric O-ring range — every standard size from 0.5 mm to 658 mm ID, grouped by cross-section, with Class B tolerances.
View full chart →BS 1806 (Legacy British Standard)
Withdrawn British Standard inch-based sizes with metric equivalents — for cross-referencing older drawings and existing inventory.
View full chart →