UK wall plug colour guide — drill sizes, screw sizes and load ratings
Yellow, red, brown, blue — every wall plug colour has a matching drill bit size and a maximum load rating. Get the drill size wrong by even 1mm and the plug spins. Get the colour wrong and the fixing fails. This guide gives you the correct drill bit, screw size, load rating and best use for each colour.
Quick reference — all four colours
Drill size is the single most important number. Use the wrong size and the plug spins or pulls.
Yellow
5 mm
drill bit
25 kg
max load
Red
6 mm
drill bit
40 kg
max load
Brown
7 mm
drill bit
60 kg
max load
Blue
10 mm
drill bit
100 kg
max load
| Colour | Drill | Screw | Screw No. |
|---|---|---|---|
Yellow | 5 mm | 3–4 mm | No.5–8 |
Red | 6 mm | 3.5–4.5mm | No.8–10 |
Brown | 7 mm | 4.5–5.5mm | No.10–14 |
Blue | 10 mm | 6–7 mm | No.14+/M6 |
Yellow wall plugs — 5mm drill bit
Drill bit
5 mm
Screw size
3–4 mm
Screw no.
No.5–8
Max load
25 kg
Works in
Solid brick, lightweight block, plasterboard (light loads only)
Avoid
Heavy loads, hollow sections, dense concrete
Common uses
Yellow is the lightest rating. If what you're hanging weighs more than a large picture frame, step up to red.
Yellow Wall Plugs — 5mm Pack
For light fixings in brick, block and plasterboard. Always pair with a 5mm masonry bit.
Red wall plugs — 6mm drill bit
Drill bit
6 mm
Screw size
3.5–4.5 mm
Screw no.
No.8–10
Max load
40 kg
Works in
Solid brick, dense block, concrete, aerated block
Avoid
Hollow block without a dedicated cavity plug
Common uses
Red is the default UK general-purpose plug. If you're unsure between yellow and red, use red.
Red Wall Plugs — 6mm Pack
The most commonly used UK wall fixing. Pairs with a 6mm masonry bit and No.8 or No.10 screw.
Brown wall plugs — 7mm drill bit
Drill bit
7 mm
Screw size
4.5–5.5 mm
Screw no.
No.10–14
Max load
60 kg
Works in
Solid brick, dense block, concrete, stone
Avoid
Plasterboard alone — use a dedicated cavity anchor for plasterboard
Common uses
"Masonry bit size for brown rawlplug" is one of the most searched fixing questions in the UK — the answer is 7mm, every time.
Brown Wall Plugs — 7mm Pack
For heavy fixings in brick and concrete. Pair with a 7mm masonry bit and a No.10–14 screw.
Blue wall plugs — 10mm drill bit
Drill bit
10 mm
Screw size
6–7 mm
Screw no.
No.14+ / M6
Max load
100 kg
Works in
Solid brick, dense concrete, natural stone
Avoid
Hollow or lightweight block — use a specialist cavity anchor
Common uses
At 10mm you're at the limit of what a plug can reliably handle. For loads above 80–100kg in concrete, a mechanical sleeve anchor is a better choice.
Blue / Frame Wall Plugs — 10mm Pack
For structural fixings up to 100kg. Pair with a 10mm masonry bit and M6 or larger screw.
Why your rawlplug spins — and how to fix it
The most common rawlplug problem is the plug spinning freely as you drive the screw in. The plug never grips the wall, the screw goes nowhere, and the hole is now too large for the plug you have. There are three causes:
Wrong drill bit size
Check you used the exact drill size for that plug colour. One millimetre too large and the plug has no wall to grip.
Worn or poor quality masonry bit
A blunt bit wanders and tears the hole slightly oversize. Replace the bit and use a sharp SDS bit for better accuracy.
Hammer action in soft brick
In soft or aerated block, hammer drill action can crumble the material around the hole. Use rotation only in soft materials.
Fix a spun hole: fill it with fast-setting wall filler or anchor epoxy, allow full cure, then re-drill to the correct size. Alternatively step up one plug colour (e.g., red → brown) and use the matching larger screw — the slightly larger plug will fill the oversize hole.
Tools and fixings on Amazon
These are the tools that make the difference between a fixing that holds and one that spins.
SDS+ Masonry Drill Bit Set (5–16mm)
One set covers every wall plug size plus rawlbolt holes up to M12. A clean SDS bit prevents the spinning plug problem.
Wall Plug Assortment Pack (Yellow, Red, Brown)
Mixed pack covers 90% of household and farm workshop jobs in one box.
Cordless SDS Hammer Drill (18V)
A hammer drill makes a big difference in brick and concrete — especially for 10mm blue plug holes and above.
Sleeve Anchor / Rawlbolt Set (M8–M16)
When a blue plug isn't enough — mechanical anchors for structural and agricultural fixings into concrete.
These are Amazon affiliate links. If you purchase through them, AgriOps earns a small commission at no extra cost to you. We only link to products relevant to the guide.
Frequently asked questions
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