Size finder · exact catalogue match

O-ring size finder

Enter the inside diameter and cross-section, or pick a standard size. You see every grade we list at that exact size, with the smallest pack price.

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Measuring a used ring?

A worn, flattened or swollen ring no longer shows its original size. We hold back direct ordering until the size is confirmed.

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Common sizes

Don't know the size? Measure itMeasure two numbers and we find the closest standard size. Have a standard number? Cross-referenceTurn an AS568, ISO 3601, JIS or BS code into ID × CS.
O-ring dimensions: ID is the inside diameter across the hole, CS is the thickness of the cord ID CS cord section
ID is the inside diameter. CS is the cross-section, or cord thickness. Both are nominal sizes of the relaxed ring.