Use the finder above to match your bolt or screw to the correct rubber washer inside diameter, then choose OD and thickness for your job. The rule of thumb: ID matches the bolt, OD sets the sealing/bearing surface (2–3x the ID for most jobs; wider for fender-style load spreading), and thickness sets the compression — 1/16" for sealing, 1/8" for cushioning, 1/4"–1/2" for spacer and bushing duty.
Every washer in our rubber washers collection lists exact OD x ID x thickness with a spec diagram. Related tools: Grommet Size Chart & Finder • Vibration Mount Size Chart • Rubber Material Guide. Ordering for production? Bulk pricing available.