Nominal ID 0.984 in with 0.139 in cross section.
AS568 O-Ring Size Converter
Convert common AS568 O-ring dash sizes to inside diameter, cross-section thickness, outside diameter, inches, and millimeters. Enter a dash size like -214, choose a preset, or enter dimensions to find the nearest common dash size.
Convert an O-ring size
Results update instantly. Dimensions are nominal; always confirm the material, tolerance, and gland design for the actual part.
AS568 -214 has a nominal outside diameter of 1.262 in / 32.05 mm.
How AS568 dash sizes work
AS568 O-ring numbers are inch-based dash sizes used for many hydraulic, pneumatic, automotive, industrial, and general sealing parts. The dash number maps to a nominal inside diameter and cross-section thickness.
For quick identification, the first digit often hints at the cross-section family: many -0xx sizes use 0.070 inch cross section, -1xx use 0.103 inch, -2xx use 0.139 inch, and -3xx use 0.210 inch. The exact dash size still matters.
Common examples
- -010: 0.239 in ID × 0.070 in CS
- -112: 0.487 in ID × 0.103 in CS
- -214: 0.984 in ID × 0.139 in CS
- -325: 1.475 in ID × 0.210 in CS
Common AS568 O-ring size chart
| Dash | ID, inches | ID, mm | Cross section | Approx. OD |
|---|
AS568 O-ring size FAQ
What size is a -214 O-ring?
An AS568 -214 O-ring is commonly listed as 0.984 inch inside diameter with a 0.139 inch cross section. That is about 24.99 mm ID and 3.53 mm cross section.
How do you calculate O-ring outside diameter?
Approximate outside diameter is inside diameter plus two times the cross section. For example, 0.984 + 2 × 0.139 = 1.262 inches.
Can I replace an AS568 O-ring with the nearest metric size?
Sometimes, but do not assume a nearest metric size will seal correctly. Match the application, material, hardness, tolerance, stretch, squeeze, temperature, fluid compatibility, and groove dimensions.