Rubber washers and gaskets both create seals, but they are not the same part. Knowing the difference helps you order the right one the first time.
What a rubber washer is
A rubber washer is a round disc with a center hole. It sits under a bolt, nut, or threaded fitting to spread load, absorb vibration, and seal around the fastener. Washers are defined by three measurements: outside diameter, inside diameter, and thickness.
What a gasket is
A gasket seals the joint between two flat mating surfaces - like a pump housing, flange, or lid. Gaskets are usually cut to match the shape of the surface and the bolt pattern, rather than a simple round-with-a-hole profile.
Which one do you need?
If you are sealing around a single bolt, hose fitting, or threaded connection, you want a washer. If you are sealing the face between two parts, you want a gasket. In both cases the material matters - see our material comparison to match the rubber to your fluids and temperature.
We stock rubber washers in every size and seven materials. Use the size chart to find yours, or contact us for custom sealing needs.