Wall Plug Drill Sizes: Chart and Guide

Where would we be without wall plugs? Whether it’s decorators or DIYers, if you’re regularly working on home improvements, you’ll never be far away from needing one of these handy plugs.

While the wall plug is a simple device largely unchanged since it was invented over 100 years ago, one factor you do need to consider is size. From choosing the right wall plug to finding the correct size screw and drill bit, this guide has everything you need to select the right tools for the job.

What Wall Plug Size Do You Need?

The main purpose of wall plugs is to provide support to screws in materials where they would otherwise struggle to get purchase, such as plasterboard or masonry. Simply drilling a screw into these brittle materials would give the thread nothing stable to latch onto, so a wall plug is inserted first, which then expands and catches onto the hole as the screw is inserted.

There are different types of wall plugs available for specific tasks, but the most common is the plastic universal wall plug, which can be used on most surfaces and is great for supporting objects around the home, like shelves.

What size wall plug you need ultimately comes down to how much weight the plug, and its screw, is expected to support. However, this is also influenced by other factors, such as the surface it’s being used on (plasterboard is weaker than solid masonry, for example).

Generally speaking, the smallest plug sizes – usually around 3mm in diameter – usually support weights around 10kg, while the largest wall plugs – usually around 10 or 12 mm – inserted into solid walls can support over 50kg.

If you’re unsure what size of wall plug you need for what you’re trying to support, look for manufacturer's guidance, either from the wall plug or screws provider.

Different Size Wall Plugs Come in Different Colours 

Handily, wall plugs are often colour-coordinated based on their size, which makes it much easier for professionals and DIYers to keep their wall plugs organised and know which is best for what job.

Wall plug colours aren’t set in stone, and some manufacturers will use different colours, so it’s always worth double-checking. However, a general rule of thumb is as follows:

1. The smallest wall plugs (3-5mm) are yellow.
2. Regular wall plugs (6mm) are red.
3. Larger wall plugs (7-8mm) are brown.
4. The largest wall plugs (10mm+) tend to be blue or grey.

Finding the Right Drill Size for Each Wall Plug

Thankfully, finding the right size of drill bit for each wall plug is really easy. All you need to do is use a drill bit that’s the same diameter as the wall plug or marginally (half a millimetre) smaller.

All universal wall plugs come in a slight cone shape, which is designed to slot neatly into a hole the same diameter as the plug. The entrance to the plug should feel secure in the entrance to the hole you’ve drilled, then you insert a screw with a diameter slightly smaller (usually around a millimetre) which pushes the cone out, creating a secure hold.

Wall Plug to Drill Bit Size Chart

Taking this table into account, a standard red wall plug at 6mm usually needs a drill bit around 5.5mm or 6mm wide, and will then take a 5mm screw. However, bear in mind that all these numbers are only a rough guide. Many wall plug manufacturers will provide details of what drill bits and screws to use with their products, so take their advice into account for the strongest hold.

Hopefully, though, this table will help make life a little easier whenever you’re on the job. Remember, if you need wall plugs, drill bits or anything else, take a look at our range, available at low trade prices with next-day delivery.