UK Anchor Bolt & Wall Plug Sizes
Wall plugs, rawlbolts, sleeve anchors and chemical anchors with drill hole sizes, load ratings and colour codes for UK fixings.
Standard Wall Plug Sizes (Colour Coded)
| Colour | Drill Size (mm) | Screw Gauge | Screw Size (mm) | Typical Use |
|---|---|---|---|---|
| Yellow | 5 | No.4–8 | 3.0–4.0 | Light shelves, pictures, switch plates |
| Red | 5.5 | No.6–10 | 3.5–5.0 | Curtain poles, brackets, towel rails |
| Brown | 7 | No.8–14 | 4.0–6.0 | Heavy shelving, TV brackets, radiators |
| Blue | 10 | No.14–18 | 6.0–8.0 | Heavy-duty, boilers, large brackets |
Rawlbolts (Expanding Anchors)
Mechanical expanding anchors for solid masonry and concrete. The bolt tightens a cone which expands a shield against the hole walls.
| Bolt Size | Drill Hole (mm) | Min. Hole Depth (mm) | Safe Load — Concrete (kg) |
|---|---|---|---|
| M6 | 10 | 45 | ~120 |
| M8 | 12 | 55 | ~200 |
| M10 | 14 | 65 | ~340 |
| M12 | 16 | 75 | ~520 |
| M16 | 22 | 95 | ~900 |
Safe loads are indicative for C20/25 concrete. Always check manufacturer data for your specific substrate.
Sleeve Anchors
Suitable for solid and hollow masonry. The sleeve expands along its full length for better load distribution in weaker substrates.
| Bolt Size | Drill Hole (mm) | Lengths Available (mm) | Typical Use |
|---|---|---|---|
| M6 | 8 | 40–100 | Light steelwork, cable trays |
| M8 | 10 | 50–130 | Racking, handrails, brackets |
| M10 | 12 | 60–160 | Steelwork, joist hangers, gates |
| M12 | 14 | 75–200 | Heavy structural connections |
Chemical (Resin) Anchors
Two-part resin injected into a drilled hole with a threaded stud. Ideal for hollow blocks, aerated concrete and close-to-edge fixings.
| Stud Size | Drill Hole (mm) | Embedment (mm) | Resin Type |
|---|---|---|---|
| M8 | 10 | 80 | Polyester / vinylester / epoxy |
| M10 | 12 | 90 | Polyester / vinylester / epoxy |
| M12 | 14 | 110 | Polyester / vinylester / epoxy |
| M16 | 18 | 125 | Vinylester / epoxy (structural) |
Use perforated sleeves (mesh sleeves) when fixing into hollow blocks with chemical anchors. Cure times vary by temperature — typically 20-45 minutes at 20°C.
Related Calculators
See the Fixings Guide by Wall Type for choosing fixings by substrate, or the UK Screw Sizes reference for screw gauges.
How We Calculate This
Frequently Asked Questions
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Last updated: April 2026
All calculations are estimates. Verify with your supplier.