What Are Penny Washers? Uses, Sizes and Buying Guide
Penny washers are wide, flat washers used to spread load over a larger surface area. They are useful when a normal washer is too small, when the material could pull through, or when you want a neater fixing over a wider area.
Quick answer: use penny washers when you need a wider bearing surface under a screw, bolt or nut. They help spread pressure, protect the material and reduce pull-through.
What does a penny washer do?
A penny washer sits between the fixing and the material. Its wider outside diameter spreads the pressure from the fixing head or nut. This makes it useful on softer materials, slotted holes, repairs and jobs where the fixing needs more support.
They are often used with bolts, machine screws, coach bolts, timber repairs, brackets, panels and general workshop hardware.
When should you use a penny washer?
Use a penny washer when the fixing head feels too small for the job, when the hole is slightly oversized, or when the material could mark, split or pull through under load.
- Timber and board: spreads pressure and helps avoid crushing softer surfaces.
- Metalwork and brackets: gives a wider, tidier bearing point.
- Repairs: useful where holes have worn larger or need extra support.
- General hardware: handy for bolts, hooks, plates, hinges and practical fixings.
Penny washer sizes explained
The size usually relates to the bolt or screw diameter it fits, such as M4, M5, M6, M8 or M10. The hole needs to suit the fixing, while the outside diameter gives the wider support area.
| Washer size | Typical use |
|---|---|
| M4 to M5 | Smaller machine screws, light hardware and furniture jobs. |
| M6 | General bolts, brackets, repair plates and medium hardware. |
| M8 to M10 | Larger bolts, heavier brackets, timber work and outdoor hardware where suitable. |
Small penny washers for light repairs
Smaller penny washers such as M4 are useful for light hardware, furniture repairs, small brackets and fixing jobs where a standard washer does not give enough surface coverage.
Larger penny washers for stronger support
Larger washers such as M8 are useful where the fixing is doing more work, or where you want a wider support area on timber, panels, brackets or heavier hardware.
Assortment packs for mixed jobs
If you regularly do repairs or workshop jobs, an assortment box can be more useful than guessing one size. It gives you a range of common penny washer sizes for different fixings.
Penny washers vs standard washers
A standard washer is smaller and is fine for many neat bolt-and-nut jobs. A penny washer is wider, so it is better when the material needs extra support or the fixing head needs a wider bearing area.
Do not use a penny washer just because it is bigger. Use it when the wider surface area actually helps the job.
Check before buying
- Match the washer hole to the screw or bolt diameter.
- Check the outside diameter gives enough support for the material.
- Choose a finish or material suitable for the environment.
- For repeat jobs, consider a larger pack or mixed assortment.
- For visible jobs, check the washer sits neatly under the fixing head.
Shop washers and practical fixings
Choose the washer size around the fixing first, then check the outside diameter gives the support you need.
FAQs
Why are they called penny washers?
The name comes from the wide, round shape. In practice, it means a washer with a larger outside diameter than a standard washer.
Are penny washers the same as repair washers?
They are often used in the same way. Both terms usually describe a wider washer used to spread load or support a fixing over a larger area.
Can penny washers be used outside?
Only if the material and finish suit the environment. For outdoor jobs, check the product material and coating before ordering.