Rubber Washer Size Chart
Every stock size we carry — 1,742 rubber washers from 3/16″ to 4″ OD, each available in Neoprene, EPDM, Nitrile, Silicone, Natural Rubber, Viton and Fiber at 60 durometer. Imperial and metric dimensions on every row. Sizes are grouped by outside diameter; every OD × ID pair below is stocked in all seven standard thicknesses from 1/16″ (1.59 mm) to 1/2″ (12.7 mm).
Need a size that isn’t listed? We cut custom sizes — request a quote. New to washer sizing? Start with how to measure OD, ID & thickness.
Every rubber washer is defined by three numbers: outside diameter (OD), inside diameter (ID) and thickness, written in that order. A "1 x 1/2 x 1/8" washer is 1" OD, 1/2" ID and 1/8" thick (25.4 x 12.7 x 3.2 mm). This page has the full size chart in inches and millimetres, the sizes most household fittings take, a quick how-to-measure method and a material guide, with links to every size we stock.
Jump to: Size chart (inch + mm) · Sizes by bolt · Faucet, hose & shower sizes · How to measure · Thickness · Materials · FAQ
How to read a washer size
Each product in our catalog shows a dimension diagram like the ones below. The big circle is the OD, the hole is the ID, and the side view shows the thickness.
3/4" OD x 1/2" ID x 1/16" Thick
1" OD x 3/4" ID x 1/8" Thick
2" OD x 1" ID x 1/8" Thick
5/8" OD x 1/4" ID x 1/16" Thick
Rubber washer size chart: inches to millimetres
Use this to convert a fractional size to decimal inches and millimetres (1 inch = 25.4 mm), then jump to that size. Each link shows every washer we list with that dimension.
| Fraction (in) | Decimal (in) | mm | Shop by OD | Shop by ID | Shop by thickness |
|---|---|---|---|---|---|
| 1/16" | 0.0625 | 1.6 | – | – | 1/16" thick |
| 3/32" | 0.0938 | 2.4 | – | – | 3/32" thick |
| 1/8" | 0.1250 | 3.2 | – | 1/8" ID | 1/8" thick |
| 3/16" | 0.1875 | 4.8 | – | 3/16" ID | 3/16" thick |
| 1/4" | 0.2500 | 6.4 | – | 1/4" ID | 1/4" thick |
| 5/16" | 0.3125 | 7.9 | 5/16" OD | 5/16" ID | – |
| 3/8" | 0.3750 | 9.5 | 3/8" OD | 3/8" ID | 3/8" thick |
| 7/16" | 0.4375 | 11.1 | 7/16" OD | 7/16" ID | – |
| 1/2" | 0.5000 | 12.7 | 1/2" OD | 1/2" ID | 1/2" thick |
| 9/16" | 0.5625 | 14.3 | 9/16" OD | 9/16" ID | – |
| 5/8" | 0.6250 | 15.9 | 5/8" OD | 5/8" ID | – |
| 11/16" | 0.6875 | 17.5 | 11/16" OD | – | – |
| 3/4" | 0.7500 | 19.1 | 3/4" OD | 3/4" ID | – |
| 13/16" | 0.8125 | 20.6 | 13/16" OD | – | – |
| 7/8" | 0.8750 | 22.2 | 7/8" OD | 7/8" ID | – |
| 15/16" | 0.9375 | 23.8 | 15/16" OD | – | – |
| 1" | 1.0000 | 25.4 | 1" OD | 1" ID | – |
| 1-1/8" | 1.1250 | 28.6 | 1-1/8" OD | – | – |
| 1-1/4" | 1.2500 | 31.8 | 1-1/4" OD | 1-1/4" ID | – |
| 1-3/8" | 1.3750 | 34.9 | 1-3/8" OD | – | – |
| 1-1/2" | 1.5000 | 38.1 | 1-1/2" OD | 1-1/2" ID | – |
| 1-5/8" | 1.6250 | 41.3 | 1-5/8" OD | – | – |
| 1-3/4" | 1.7500 | 44.5 | 1-3/4" OD | – | – |
| 2" | 2.0000 | 50.8 | 2" OD | – | – |
| 2-1/4" | 2.2500 | 57.2 | 2-1/4" OD | – | – |
| 2-1/2" | 2.5000 | 63.5 | 2-1/2" OD | – | – |
| 2-3/4" | 2.7500 | 69.9 | 2-3/4" OD | – | – |
| 3" | 3.0000 | 76.2 | 3" OD | – | – |
| 3-1/2" | 3.5000 | 88.9 | 3-1/2" OD | – | – |
| 4" | 4.0000 | 101.6 | 4" OD | – | – |
Rubber washer sizes by bolt or screw
The washer ID should match the bolt's nominal diameter (rubber stretches slightly, so it grips) or go one size up for a loose slip fit. The OD is usually 2 to 3 times the ID so the load spreads out.
| Fits bolt / screw | Metric near-equivalent | Washer ID | Typical OD range | Common thickness | Shop |
|---|---|---|---|---|---|
| #6 screw | M3 (3 mm) | 1/8" (3.2 mm) | 5/16" – 1/2" | 1/16", 3/32" | 1/8" ID washers |
| #10 screw | M5 (5 mm) | 3/16" (4.8 mm) | 1/2" – 3/4" | 1/16", 3/32", 1/8" | 3/16" ID washers |
| 1/4" bolt | M6 (6 mm) | 1/4" (6.4 mm) | 5/8" – 1" | 1/16", 1/8", 3/16" | 1/4" ID washers |
| 5/16" bolt | M8 (8 mm) | 5/16" (7.9 mm) | 3/4" – 1-1/4" | 1/16", 1/8", 3/16" | 5/16" ID washers |
| 3/8" bolt | M10 (10 mm) | 3/8" (9.5 mm) | 7/8" – 1-1/2" | 1/8", 3/16", 1/4" | 3/8" ID washers |
| 1/2" bolt | M12 (12 mm) | 1/2" (12.7 mm) | 1-1/8" – 1-3/4" | 1/8", 3/16", 1/4", 3/8" | 1/2" ID washers |
| 5/8" bolt | M16 (16 mm) | 5/8" (15.9 mm) | 1-3/8" – 2" | 3/16", 1/4", 3/8" | 5/8" ID washers |
| 3/4" bolt | M20 (20 mm) | 3/4" (19.1 mm) | 1-5/8" – 2-1/4" | 3/16", 1/4", 3/8", 1/2" | 3/4" ID washers |
| 1" bolt / pipe | – | 1" (25.4 mm) | 1-1/2" – 3" | 1/4", 3/8", 1/2" | 1" ID washers |
Metric bolts are close to, not identical with, the inch sizes above. See metric rubber washers for the nearest inch size to each mm dimension.
Common household washer sizes
These are typical sizes for US fittings. Brands vary, so measure the old washer before you order if you can.
| Fitting | Typical washer size (OD x ID x thickness) | Shop |
|---|---|---|
| Shower head / shower arm (1/2" NPT) | about 3/4" x 1/2" x 1/16"–1/8" (19.1 x 12.7 x 1.6–3.2 mm) | 3/4 x 1/2 x 1/16 · all shower head washers · guide |
| Garden hose and washing machine fill hose (3/4" GHT) | about 1" OD x 5/8"–3/4" ID x 1/16"–1/8" (25.4 x 15.9–19.1 x 1.6–3.2 mm) | 1 x 3/4 x 1/8 · all hose washers · guide |
| Faucet / tap seat washer | trade sizes 00 to 3/4, roughly 1/2" to 7/8" OD | faucet washers · trade size chart |
| Outdoor spigot / hose bibb seat | usually the 3/4 trade size, around 13/16"–7/8" OD | 13/16" OD · 7/8" OD |
| Toilet tank bolts, spud and tank-to-bowl | varies by toilet model; measure the old part | toilet washer guide |
| Sink drain slip joint | sized to the tailpiece: 1-1/4" or 1-1/2" | slip joint guide |
How to measure a rubber washer
- Outside diameter: measure straight across the widest point of the washer, through the centre. A digital or vernier caliper is best; a ruler marked in 1/16" or millimetres works for larger washers.
- Inside diameter: measure across the hole at its widest point, or use the caliper's inside jaws.
- Thickness: lay the washer flat and close the caliper on it gently. Don't squeeze, because rubber compresses and reads thin.
- Convert and round: find the nearest size in the chart above. For example, 19 mm is 3/4" (19.1 mm).
Old washer worn, cracked or squashed? Measure what it sits on instead. The ID should match the bolt or pipe diameter, and the OD should fit inside the nut, seat or recess. Old washers usually measure thinner than they started, so round the thickness up. The full step-by-step guide is how to measure a rubber washer, and the size finder matches measurements to a product.
Which thickness do you need?
| Thickness | mm | Best for |
|---|---|---|
| 1/16" | 1.6 | Light sealing, electronics, tight clearances, shower heads |
| 3/32" – 1/8" | 2.4 – 3.2 | General plumbing, faucets, hoses, standard sealing |
| 3/16" – 1/4" | 4.8 – 6.4 | Vibration damping, outdoor fixtures, uneven surfaces |
| 3/8" – 1/2" | 9.5 – 12.7 | Heavy compression, spacing, shock absorption |
Rubber washer materials: which one to choose
Size decides the fit; material decides how long the washer lasts. Temperature ranges are typical service ranges for each compound.
| Material | Typical temperature range | Oil & fuel | Weather / UV | Best for |
|---|---|---|---|---|
| Neoprene | -40°F to 250°F (-40°C to 121°C) | Good | Excellent | General purpose, HVAC, marine (guide) |
| EPDM | -65°F to 300°F (-54°C to 149°C) | Poor | Best | Outdoor, roofing, hot and cold water (guide) |
| Nitrile (Buna-N) | -40°F to 250°F (-40°C to 121°C) | Best | Poor | Oil, fuel, hydraulics (guide) |
| Silicone | -100°F to 450°F (-73°C to 232°C) | Poor | Excellent | High heat, food contact, appliances (guide) |
| Viton (FKM) | -15°F to 400°F (-26°C to 204°C) | Excellent | Excellent | Chemicals, solvents, high heat with fuel (guide) |
| Natural rubber | -65°F to 180°F (-54°C to 82°C) | Poor | Poor | Abrasion, cushioning, low cost (guide) |
| Fiber | -40°F to 300°F (-40°C to 149°C) | Good | Good | Pipe fittings, flanges, fuel and oil unions (guide) |
Not sure? Neoprene is the all-round choice for water and general use; pick EPDM for sun and weather, nitrile for oil and fuel, silicone for heat, and Viton for chemicals. The material comparison goes into more detail.
Shop by outside diameter (OD)
5/16" OD · 3/8" OD · 7/16" OD · 1/2" OD · 9/16" OD · 5/8" OD · 11/16" OD · 3/4" OD · 13/16" OD · 7/8" OD · 15/16" OD · 1" OD · 1-1/8" OD · 1-1/4" OD · 1-3/8" OD · 1-1/2" OD · 1-5/8" OD · 1-3/4" OD · 2" OD · 2-1/4" OD · 2-1/2" OD · 2-3/4" OD · 3" OD · 3-1/2" OD · 4" OD
Shop by inside diameter (ID)
1/8" ID · 3/16" ID · 1/4" ID · 5/16" ID · 3/8" ID · 7/16" ID · 1/2" ID · 9/16" ID · 5/8" ID · 3/4" ID · 7/8" ID · 1" ID · 1-1/4" ID · 1-1/2" ID
Shop by thickness
1/16" thick · 3/32" thick · 1/8" thick · 3/16" thick · 1/4" thick · 3/8" thick · 1/2" thick
Frequently asked questions
How are rubber washer sizes measured?
By three dimensions in this order: outside diameter (OD), inside diameter (ID) and thickness. A 3/4 x 1/4 x 1/8 washer has a 3/4 inch OD, a 1/4 inch ID and is 1/8 inch thick.
How do I measure a rubber washer without calipers?
Use a ruler marked in 1/16 inch or millimetres. Measure straight across the widest point through the centre for the OD, across the hole for the ID, and stand the washer on edge against the ruler for the thickness. For small washers, measuring the bolt it fits and the recess it sits in is often more accurate.
What size rubber washer fits a 1/4 inch bolt?
A washer with a 1/4 inch (6.4 mm) ID. Typical ODs for that ID run from 5/8 inch to 1 inch, depending on how much bearing surface you need.
What size washer does a garden hose use?
US garden hoses and washing machine fill hoses use 3/4 inch garden hose thread. The flat washer is typically about 1 inch OD with a 5/8 to 3/4 inch ID, in 1/16 to 1/8 inch thickness.
What size washer does a shower head use?
Most US shower arms are 1/2 inch NPT, and the washer in the shower head nut is typically about 3/4 inch OD x 1/2 inch ID x 1/16 to 1/8 inch thick.
Should a rubber washer be tight on the bolt?
The ID should match the bolt's nominal size. Rubber flexes, so an exact-size ID grips snugly without tearing. For a loose slip fit, go one ID size up.
What is the difference between silicone and rubber washers?
Silicone is one type of rubber. It handles a much wider temperature range (about -100 F to 450 F) than neoprene or EPDM and is used for heat and food contact, but it has poor oil and fuel resistance and lower tear strength.
How do I convert a washer size from mm to inches?
Divide the millimetres by 25.4, then round to the nearest 1/16 inch. For example, 12.7 mm is 0.5 inch (1/2 inch) and 19 mm is about 0.75 inch (3/4 inch).
Need a size or material that isn't listed? Browse the full catalog, see bulk and wholesale, or contact us about custom sizes.