Never use nylon wall plugs or plasterboard anchors for safety-critical fixings. Handrails, stair rails, banisters, balustrades, gates, ladders, climbing or play equipment, overhead fixings, and anything else whose failure could cause a fall or injury need a fixing designed and rated for that purpose — typically a through-bolt, a mechanical anchor or a resin-bonded anchor with a published load rating (and, for structural use, a European Technical Assessment). If you are not certain the wall and the fixing are up to the job, get advice from a builder or structural engineer.
Wall Plugs, Fixings & Drill Bit Sizing Guide
Choosing the right wall plug, fixing, and drill bit combination is the difference between a secure shelf and a pile of rubble on your floor. The UK uses a colour-coded wall plug system that makes selection easier — but only if you know which colour matches which screw, which drill bit to use, and what type of wall you’re fixing into. This guide covers everything you need to get your fixings right first time.
Key Takeaway
The three things you must match are: wall plug size (by diameter; colour codes differ between brands), drill bit diameter (must match the wall plug, not the screw), and screw gauge (each plug size accepts a range of screw gauges). Get any of these wrong and your fixing will either be too loose to hold or too tight to insert.
Wall Plug Colour Chart — Quick Reference
Wall plug colour codes are brand-specific. The table below uses Rawlplug’s UNO range; fischer sells its SX, SX Plus and DuoPower plugs by size rather than by a colour code. Go by the diameter printed on the packet.
| Colour | Plug Size | Drill Bit | Screw | Rawlplug load in solid brick (tension) |
|---|---|---|---|---|
| 🟡 Yellow | 5mm | 5mm | As on the packaging | 0.43 kN |
| 🔴 Red | 6mm | 6mm | As on the packaging | 0.71 kN |
| 🟤 Brown | 7mm | 7mm | As on the packaging | 0.86 kN |
| 🔵 Blue | 8mm | 8mm | As on the packaging | 0.86 kN |
| ⚪ Grey | 10mm | 10mm | As on the packaging | 1.00 kN |
Recommended Drill Bit Sets
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Plug colours on this page follow Rawlplug’s UNO range (yellow 5mm, red 6mm, brown 7mm, blue 8mm, grey 10mm). Other brands use different colours, so go by the diameter printed on the plug or box. Loads are Rawlplug’s recommended tension loads per plug in solid brick; they are much lower in weaker walls, so check the figure for your wall.
Get the free Drill Bit & Wall-Plug Size Chart (PDF)
Every drill size, wall-plug colour & tap size on one printable sheet.
See the full breakdown: Wall Plug Colour Chart
Drill Bit Sizes for Wall Plugs
The golden rule: your drill bit must match the wall plug diameter, not the screw. A 6mm plug (red in Rawlplug’s UNO range) needs a 6mm drill bit. The screw is deliberately larger than the plug’s internal hole, which is what creates the expansion grip. If you drill too large, the plug won’t grip. Too small, and you won’t be able to insert the plug.
Key Rule
For standard nylon plugs, drill bit diameter = plug diameter. In Rawlplug’s UNO range: yellow 5mm, red 6mm, brown 7mm, blue 8mm, grey 10mm. Other brands use different colours, so go by the diameter on the packet. The bit size does not change with the screw you use.
Full guide: Drill Bit Sizes for Wall Plugs
Plasterboard vs Masonry Fixings
Expansion-only masonry plugs are designed for solid walls such as brick, block, concrete and stone, and are not designed for plasterboard. Universal plugs such as Rawlplug UNO and fischer DuoPower do have published plasterboard loads, though much lower than in masonry. Plasterboard requires specialist fixings that grip the board itself or spread the load across a larger area.
Important
Don’t use expansion-only masonry plugs in plasterboard. Use purpose-made plasterboard fixings such as spring toggles, gravity toggles, or self-drill fixings. For heavy loads on plasterboard, always try to fix into the timber studs behind the board.
Detailed guides: Plasterboard Fixings Guide | Masonry Fixings Guide
Hanging Heavy Items
Wall-mounted TVs, heavy shelves, radiators, and kitchen cabinets all need careful fixing. The key questions are: what type of wall (masonry or plasterboard), how heavy is the item, and is there a stud available to fix into? For masonry walls, choose plugs whose published load for your wall covers the item: Rawlplug gives 0.86 kN per 7mm (brown) UNO plug and 1.00 kN per 10mm (grey) UNO plug in solid brick, in tension. For plasterboard, you’ll need heavy-duty toggle fixings or — ideally — to locate and fix directly into timber studs.
Full guide: What Wall Plug for Heavy Items?
Browse by Topic
- Wall Plug Colour Chart — complete UK colour coding system
- Drill Bit Sizes for Wall Plugs — which bit for which plug
- Screw Sizes for Wall Plugs — screw gauge matching guide
- Wall Plug Sizes — comprehensive size guide
- Plasterboard Fixings Guide — fixings for hollow walls
- Masonry Fixings Guide — fixings for brick, block & concrete
- What Wall Plug for Heavy Items? — TVs, shelves, radiators
- Types of Wall Fixings — every fixing type explained
- Wall Plug Compatibility Chart — master quick-reference
Recommended Wall Plugs & Fixings
| Product | Type | Best For | Link |
|---|---|---|---|
| Fischer SX 6mm Wall Plugs (50 Pack) | Standard expansion plug | General-purpose masonry fixing | View on Amazon |
| Fischer DuoPower 6x30mm (100 Pack) | Universal plug (masonry + plasterboard) | Many wall types (fischer publishes a load for each) | View on Amazon |
| GripIt 15mm Plasterboard Fixings (4 Pack) | Plasterboard toggle | Heavy loads on plasterboard (check GripIt’s published load) | View on Amazon |
| Bosch 8-Piece Masonry Drill Bit Set | Masonry drill bits | Complete set for all wall plug sizes | View on Amazon |
| Rawlplug Mixed Wall Plug Kit (272 Pieces) | Assorted plugs + screws | All-in-one kit for most jobs | View on Amazon |
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Where to Buy Wall Plugs & Fixings
Wall Plug Assortment Kits on Amazon
How we compile this guide
We cross-reference compatibility details against manufacturer specifications where available, official tool manuals, and the physical standards that govern fitment (bore sizes, arbor diameters, voltage platforms, connector types). We prioritise primary sources over retailer listings, flag anything we can’t confirm, and re-verify the data on a regular cycle. Where we give a buying recommendation, we tell you the reasoning — not just the link. More on our method →