Product family
Standard O-Rings
Standard-size O-rings across the full AS568 inch range and every major international metric standard — AS568, ISO 3601, ISO 6149, DIN 3771, JIS B 2401, BS 1806, BS 4518, SMS 1586 and NF T 47-501. We mold them to your compound, hardness and color — and give you a free, ungated size chart plus a metric tolerance calculator for every standard we build to.
Overview
Every AS568 dash number and metric standard
When your drawing calls out a standard O-ring size, ARC builds it to that standard in the material your application actually needs — rather than selling a fixed catalog of stock parts. We cover the complete AS568 inch dash-number series (-001 through -475) and the full set of international metric standards, so a size specified to ISO 3601, ISO 6149, DIN 3771, JIS B 2401, BS 1806, BS 4518, SMS 1586 or NF T 47-501 is molded to the correct cross-section and tolerance. Every standard we build to has a free, ungated size chart below, plus a metric O-ring tolerance calculator for groove and gland dimensions. Need a size no standard table lists? That’s a custom O-ring — and we build those too. All standard and custom O-rings are made to spec, Made in USA, under ISO 9001:2015 and IATF 16949:2016.
Have a print or a spec in mind? Request a quote →
Capabilities
Complete AS568 dash-number range (-001 through -475)
Every major metric standard: ISO 3601, ISO 6149, DIN 3771, JIS B 2401, BS 1806, BS 4518, SMS 1586, NF T 47-501
Molded to your compound, Shore hardness and color — not a bin part
Free, ungated size charts plus a metric tolerance calculator
Tolerances to ISO 3601 / AS568 quality grades
Cross-referencing the same size across international standards
Prototype through production with first-article inspection
ISO 9001:2015 & IATF 16949:2016 certified, Made in USA
What we make
Standard size systems we build to
The US aerospace standard — 380+ dash-number sizes from -001 to -475, the most widely used O-ring sizing system.
The international metric O-ring standard defining sizes, tolerances and quality-acceptance grades.
Metric sizes for hydraulic port and fluid-power sealing.
German metric O-ring sizing used across a wide range of European equipment.
Japanese Industrial Standard metric O-rings for fixed and dynamic sealing.
British Standard inch (1806) and metric (4518) O-ring size series.
Reference
Size charts & the tolerance calculator
Every size chart and the metric tolerance calculator for the standards we build to — free and ungated. Need a size that isn’t in a standard table? See Custom O-Rings.
Materials we mold to
Industries we serve
Where it's used
Typical applications
Need standard O-rings in the right compound?
Send your dash number, metric size or drawing — our engineers confirm the compound, tooling and a path to production.
Standard O-ring sizes & international standards
American Rubber Corporation is a leading manufacturer and distributor of custom and standard O-rings. Shortly after O-rings first came into common use, it became clear that agreed standards for O-ring sizes and tolerances would be beneficial, and various government and engineering organizations have since produced a multitude of O-ring standards. Below is a brief overview of the standards most often used and referenced by our customers — each with a link to a size chart listing all known sizes for that standard.
Tolerances
Most of the standards referenced here specify acceptable tolerance ranges. With the exception of our AS568 size chart, our size-reference charts do not list tolerances, since these vary between the issuing organizations. To simplify tolerances for the standard O-rings we sell, refer to either the AS568 size chart (for American Standard sizes) or our Metric O-Ring Tolerances calculator (for any metric O-ring).
International O-ring size reference table
Our international size cross-reference table shows the common international size standards and lets you cross-reference one standard against another. Note that no tolerances or materials are taken into consideration in the cross-reference chart.
Types of standard O-ring
AS568
Published by the Society of Automotive Engineers (SAE), AS568 is the most common size reference used by American companies. It specifies inside diameters, cross-sections, tolerances and size identification codes (dash numbers) for O-rings used in sealing applications and for straight-thread tube-fitting boss gaskets. Check the AS568 size chart →
BS 1806
Issued by the British Standards Institution, BS 1806 lists all Imperial standard sizes. It includes all five main cross-section groups in AS568 plus several sizes that fall between AS568 sizes. BS 1806 has been superseded by BS ISO 3601, but remains widely referenced in certain industries and regions for cross-reference purposes. Check the BS 1806 size chart →
ISO 3601
Issued by the International Organization for Standardization, ISO 3601 contains two groups of O-rings, Class A and Class B. Class A corresponds to the American standard AS568B in its current format (the 900-series tube-fitting O-rings are not included), and its ISO 3601-1 size code is the same as the AS568 dash number. Class B allows substitution of O-rings in technically acceptable, economical metric sizes that fit into metric grooves; the first digit of the size code indicates the cross-section group (A–E) and the last four digits indicate the inside diameter rounded to a tenth of a millimeter. Check the ISO 3601 size chart →
BS 4518
Also issued by the British Standards Institution, BS 4518 identifies British Standard metric sizes. The size code is a four-digit number indicating the O-ring ID in tenths of a millimeter, followed by a hyphen and two digits indicating the cross-section, also in tenths of a millimeter. Check the BS 4518 size chart →
SMS 1586
SMS 1586 is the Swedish Mechanical Standard for O-rings (Sveriges Mekanstandardisering). O-rings are identified by ID and cross-section, similar to DIN 3771, and are classified into two groups: a dynamic-and-static group (marked D in our table) and a mainly-static group (marked S). Check the SMS 1586 size chart →
DIN 3771
Issued by the German Institute for Standards (Deutsches Institut für Normung), DIN 3771 identifies O-ring sizes by ID x cross-section, optionally followed by a letter indicating quality level (N — normal; S — special) and a code indicating the rubber polymer and IRHD hardness. Check the DIN 3771 size chart →
NF T 47-501
NF T 47-501 is issued by the Association Française de Normalisation (French Standards Institute) and is very similar to ISO 3601-1 in both the sizes included and the size reference. Size codes use a letter for each of five cross-section groups (A–E), four digits for ID (rounded to 0.1 mm), a second letter for Precision Class (A for aerospace, G for general purpose) and a third letter for Visual Class (N at 1.0 AQL, S at 0.65 AQL). Check the NF T 47-501 size chart →
JIS B 2401
JIS B 2401 is a Japanese Industrial Standard for O-ring sizes, often referred to as Japanese Metrics. It is organized into four series by application — P series (moving/dynamic), G series (fixed/static), S series (special sizes) and V series (vacuum flange) — with ascending number codes completing the size reference. Check the JIS B 2401 size chart →
ISO 6149
ISO 6149 specifies O-rings designed for use in metric tube fittings. It includes 13 different sizes and calls out the metric thread size for each O-ring size. Check the ISO 6149 size chart →
Generic metric O-ring sizes
We also provide a table of the most common metric sizes that may or may not match any international standard size. We can supply most of these, as most factories have established tooling for these generic metric sizes. Check the generic metric size chart →