# AS568 O-Ring Dash Size Chart and Reference

> Source: https://netray.co/tools/as568-o-ring-dash-size-reference
> Publisher: Netray (netray.co), AI and integration engineering for ERP and manufacturing systems.
> Section: Free Tools

## Short answer

Look up AS568 dash numbers with nominal inside diameter, cross-section, outside diameter and metric equivalents for the common series.

## Category

engineering-plm

## Industry

Fluid Power and Sealing

## Audience

- Estimator
- Buyer
- Design engineer

## Tool

**Kind:** worksheet

**Mode:** reference

**Columns:**

#### Dash no.

**Key:** dash

**Type:** text

#### CS series

**Key:** series

**Type:** text

#### Nominal ID (in)

**Key:** id

**Type:** number

**Format:** decimal

#### Nominal CS (in)

**Key:** cs

**Type:** number

**Format:** decimal

#### Nominal OD (in)

**Key:** od

**Type:** number

**Expr:** id + 2 * cs

**Format:** decimal

#### ID (mm)

**Key:** id_mm

**Type:** number

**Expr:** id * 25.4

**Format:** decimal

#### CS (mm)

**Key:** cs_mm

**Type:** number

**Expr:** cs * 25.4

**Format:** decimal

**Rows:**

**Dash:** -004

**Series:** 0xx

**Id:** 0.07

**Cs:** 0.07

**Dash:** -005

**Series:** 0xx

**Id:** 0.101

**Cs:** 0.07

**Dash:** -006

**Series:** 0xx

**Id:** 0.114

**Cs:** 0.07

**Dash:** -007

**Series:** 0xx

**Id:** 0.145

**Cs:** 0.07

**Dash:** -008

**Series:** 0xx

**Id:** 0.176

**Cs:** 0.07

**Dash:** -009

**Series:** 0xx

**Id:** 0.208

**Cs:** 0.07

**Dash:** -010

**Series:** 0xx

**Id:** 0.239

**Cs:** 0.07

**Dash:** -011

**Series:** 0xx

**Id:** 0.301

**Cs:** 0.07

**Dash:** -012

**Series:** 0xx

**Id:** 0.364

**Cs:** 0.07

**Dash:** -013

**Series:** 0xx

**Id:** 0.426

**Cs:** 0.07

**Dash:** -014

**Series:** 0xx

**Id:** 0.489

**Cs:** 0.07

**Dash:** -015

**Series:** 0xx

**Id:** 0.551

**Cs:** 0.07

**Dash:** -016

**Series:** 0xx

**Id:** 0.614

**Cs:** 0.07

**Dash:** -017

**Series:** 0xx

**Id:** 0.676

**Cs:** 0.07

**Dash:** -018

**Series:** 0xx

**Id:** 0.739

**Cs:** 0.07

**Dash:** -019

**Series:** 0xx

**Id:** 0.801

**Cs:** 0.07

**Dash:** -020

**Series:** 0xx

**Id:** 0.864

**Cs:** 0.07

**Dash:** -102

**Series:** 1xx

**Id:** 0.049

**Cs:** 0.103

**Dash:** -103

**Series:** 1xx

**Id:** 0.081

**Cs:** 0.103

**Dash:** -104

**Series:** 1xx

**Id:** 0.112

**Cs:** 0.103

**Dash:** -105

**Series:** 1xx

**Id:** 0.143

**Cs:** 0.103

**Dash:** -106

**Series:** 1xx

**Id:** 0.174

**Cs:** 0.103

**Dash:** -107

**Series:** 1xx

**Id:** 0.206

**Cs:** 0.103

**Dash:** -108

**Series:** 1xx

**Id:** 0.237

**Cs:** 0.103

**Dash:** -109

**Series:** 1xx

**Id:** 0.299

**Cs:** 0.103

**Dash:** -110

**Series:** 1xx

**Id:** 0.362

**Cs:** 0.103

**Dash:** -111

**Series:** 1xx

**Id:** 0.424

**Cs:** 0.103

**Dash:** -112

**Series:** 1xx

**Id:** 0.487

**Cs:** 0.103

**Dash:** -113

**Series:** 1xx

**Id:** 0.549

**Cs:** 0.103

**Dash:** -114

**Series:** 1xx

**Id:** 0.612

**Cs:** 0.103

**Dash:** -115

**Series:** 1xx

**Id:** 0.674

**Cs:** 0.103

**Dash:** -116

**Series:** 1xx

**Id:** 0.737

**Cs:** 0.103

**Dash:** -201

**Series:** 2xx

**Id:** 0.171

**Cs:** 0.139

**Dash:** -202

**Series:** 2xx

**Id:** 0.234

**Cs:** 0.139

**Dash:** -203

**Series:** 2xx

**Id:** 0.296

**Cs:** 0.139

**Dash:** -204

**Series:** 2xx

**Id:** 0.359

**Cs:** 0.139

**Dash:** -205

**Series:** 2xx

**Id:** 0.421

**Cs:** 0.139

**Dash:** -206

**Series:** 2xx

**Id:** 0.484

**Cs:** 0.139

**Dash:** -207

**Series:** 2xx

**Id:** 0.546

**Cs:** 0.139

**Dash:** -208

**Series:** 2xx

**Id:** 0.609

**Cs:** 0.139

**Dash:** -209

**Series:** 2xx

**Id:** 0.671

**Cs:** 0.139

**Dash:** -210

**Series:** 2xx

**Id:** 0.734

**Cs:** 0.139

**Dash:** -211

**Series:** 2xx

**Id:** 0.796

**Cs:** 0.139

**Dash:** -212

**Series:** 2xx

**Id:** 0.859

**Cs:** 0.139

**Dash:** -213

**Series:** 2xx

**Id:** 0.921

**Cs:** 0.139

**Dash:** -214

**Series:** 2xx

**Id:** 0.984

**Cs:** 0.139

**Dash:** -215

**Series:** 2xx

**Id:** 1.046

**Cs:** 0.139

**Dash:** -216

**Series:** 2xx

**Id:** 1.109

**Cs:** 0.139

**Dash:** -309

**Series:** 3xx

**Id:** 0.412

**Cs:** 0.21

**Dash:** -310

**Series:** 3xx

**Id:** 0.475

**Cs:** 0.21

**Dash:** -311

**Series:** 3xx

**Id:** 0.537

**Cs:** 0.21

**Dash:** -312

**Series:** 3xx

**Id:** 0.6

**Cs:** 0.21

**Dash:** -313

**Series:** 3xx

**Id:** 0.662

**Cs:** 0.21

**Dash:** -314

**Series:** 3xx

**Id:** 0.725

**Cs:** 0.21

**Dash:** -315

**Series:** 3xx

**Id:** 0.787

**Cs:** 0.21

**Dash:** -316

**Series:** 3xx

**Id:** 0.85

**Cs:** 0.21

**Notes:** Nominal values for the standard AS568 series, listed as a quick lookup. The 0xx series is 0.070 in, 1xx is 0.103 in, 2xx is 0.139 in, 3xx is 0.210 in and 4xx is 0.275 in nominal cross-section. Outside diameter is calculated as ID plus two cross-sections. Always confirm size and tolerances against the current AS568 standard and your supplier drawing; metric O-rings are not the same as AS568 inch sizes, even when close.

## Content

**Intro:** AS568 assigns each standard inch-series O-ring a dash number that fixes its inside diameter and cross-section. This searchable chart lists nominal ID, cross-section, calculated OD and millimetre equivalents so estimators and buyers can confirm a size in seconds.

**Sections:**

#### How to use the chart

**Body:** Type a dash number such as 210, or an ID or series, into the search box to filter the table. Each row shows the nominal inside diameter and cross-section in inches, the calculated outside diameter and the metric conversions. Use it to confirm a customer's callout, cross-check a supplier quote line, or find the nearest standard size before you ask for a custom mould.

**Bullets:**

- Dash numbers beginning 0 or 1 are the smaller 0.070 in and 0.103 in sections.
- A 2xx dash is a 0.139 in section; 3xx is 0.210 in; 4xx is 0.275 in.
- Drawings often write the size as 2-210 or AS568-210; both refer to the same dash 210 ring.

#### How the numbering works

**Body:** AS568 dash numbers encode the cross-section series in the leading digit or digits and the ID size sequence in the last two. Within a series, nominal IDs step upward in fixed increments, which is why 2xx IDs rise by roughly 0.0625 in at larger sizes. The standard also defines the tolerances for ID and cross-section, which grow with size. Because tolerances are part of the callout, the nominal values listed here are not enough to check an inspection report.

#### Common mistakes

**Body:** The two main mistakes are confusing inch and metric O-rings, and ordering by ID alone. A 25 mm ID metric ring is not the same as any dash size. A dash 210 (0.734 in ID, 0.139 in CS) is not interchangeable with a metric ring of similar ID but a different cross-section. Always carry both ID and cross-section into the ERP item description, along with the compound and durometer.

#### Using it with ERP item masters

**Body:** Most shops store O-rings as stock items with a description like 'O-RING 2-210 FKM 75'. Standardising the dash number, material code and durometer in a fixed pattern makes the item master searchable and prevents duplicates. Add the cross-section and ID as attributes so engineers can filter. The chart's exportable Excel form works as a cleanup key for matching legacy descriptions to the correct size.

**Cta:** If your item master has hundreds of free-text O-ring descriptions, we can show how a private assistant normalises them to a dash number, compound and durometer without sending data off site.

**Faq:**

#### What does AS568 dash number mean?

**Answer:** It is the size code for a standard inch-series O-ring. The number fixes the nominal inside diameter and the cross-section, and the series determines the section. For example dash 210 is 0.734 in ID by 0.139 in cross-section.

#### What is the size of an AS568-210 O-ring?

**Answer:** Nominal inside diameter is 0.734 inches and nominal cross-section is 0.139 inches, which gives an outside diameter of 1.012 inches. In millimetres that is about 18.64 mm ID by 3.53 mm cross-section.

#### Are AS568 O-rings the same as metric O-rings?

**Answer:** No. AS568 is an inch-based series with its own dash numbers. Metric O-rings follow ISO 3601 sizes and are specified by ID and cross-section in millimetres. Some sizes are close but not identical, so do not substitute without checking both dimensions.

#### Does this list every AS568 size?

**Answer:** No. It shows the common sizes in the 0xx to 3xx series as a quick lookup, and the full standard has many more, including the 4xx series. Check the current AS568 document or your supplier catalogue for the complete range and tolerances.

## Search terms

as568 dash size chart, o-ring size chart, as568 o-ring sizes, o-ring dash number lookup, o-ring 210 size, o-ring cross section by dash number, o-ring inside diameter chart mm, as568 series 2xx

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