Circular Saw Blade Sizes — Which Diameter Do You Need?
Circular saw blades come in a wide range of diameters, and using the correct size is essential for both safety and performance. Your saw is designed for a specific blade diameter — you cannot fit a larger blade, and while a smaller blade may physically fit, it’s generally not recommended. This guide covers every common circular saw blade diameter in the UK and which saws they fit.
Quick Answer
The most common circular saw blade sizes in the UK are: 165mm (most 18V cordless saws), 190mm (larger corded saws), 216mm (compact mitre saws), and 254mm/305mm (sliding mitre saws). Always match the blade diameter to your saw’s rated size.
Common Blade Diameters
| Diameter | Imperial | Typical Saws | Common Bore |
|---|---|---|---|
| 85mm | 3⅜” | Mini/compact circular saws | 15mm |
| 136mm | 5⅜” | Small cordless circular saws | 20mm |
| 160mm | 6¼” | Festool TS 55 plunge saw | 20mm |
| 165mm | 6½” | Most 18V cordless circular saws (DeWalt, Makita, Bosch; Milwaukee uses 15.87mm) | 20mm |
| 184mm | 7¼” | Some corded circular saws | 20mm or 30mm |
| 190mm | 7½” | Larger corded circular saws | 30mm |
| 210mm | 8¼” | Some mitre saws and table saws | 30mm |
| 216mm | 8½” | Compact mitre saws | 30mm |
| 250mm | 10″ | Table saws, some mitre saws | 30mm |
| 254mm | 10″ | Table saws (Imperial equivalent) | 30mm |
| 305mm | 12″ | Sliding mitre saws (large) | 30mm |
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Which Size Do I Need?
Check the label on your saw or the blade currently fitted. The blade diameter is always clearly marked (e.g., “DCS391 — 165mm blade”). You must use the exact diameter your saw is rated for. A larger blade physically won’t fit, and a smaller blade leaves the blade guard unable to function properly and reduces cutting depth.
Important: Never fit a blade larger than your saw’s maximum rated diameter. The blade guard will not cover it properly, creating a serious safety hazard. Some saws can accept a slightly smaller blade (e.g., a 160mm blade in a 165mm saw), but this reduces cutting depth and may affect guard function. See our guide: Can You Use a Smaller Circular Saw Blade?
165mm vs 190mm — What’s the Difference?
The 165mm blade is the standard for cordless circular saws in the UK, offering a maximum cutting depth of about 55mm at 90°. The 190mm blade is more common on corded circular saws and gives a deeper maximum cut of around 66mm. If you have an 18V cordless saw from DeWalt, Makita, Milwaukee, or Bosch, you almost certainly need 165mm blades.
Related guides: Circular Saw Bore Sizes | Mitre Saw Blade Sizes | Saw Blade Compatibility Guide
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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 →