Clipper Blade Sizes Explained: #4F vs #7F vs #10 vs #30 — Which One Do You Need?
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Choosing the right clipper blade size is one of the most common questions pet owners and groomers face. Use the wrong blade and you risk cutting too short, leaving uneven patches, or even irritating your pet's skin. This guide breaks down the most popular A5-style blade sizes so you can groom with confidence.
How Clipper Blade Numbers Work
Here's the key rule: the higher the blade number, the shorter the cut. A #4F leaves more coat length; a #30 cuts very close to the skin. The "F" suffix stands for finish — these blades have finer teeth that leave a smoother, more polished result compared to skip-tooth blades (used mainly for de-matting).
Blade Size Quick-Reference Chart
| Blade Size | Cut Length | Best For |
|---|---|---|
| #4F | ~9.5 mm | Long, fluffy body trims on Poodles, Doodles, Spaniels |
| #5F | ~6.3 mm | Medium-length body work, summer cuts |
| #7F | ~3.2 mm | All-over body clips, short breed trims (Schnauzers, Cockers) |
| #10 | ~1.6 mm | Sanitary areas, paw pads, face, ears |
| #15 | ~1.2 mm | Close face and paw work, surgical prep |
| #30 | ~0.5 mm | Very close cuts, surgical/veterinary use |
#4F — The Long-Coat Favourite
The #4F blade leaves about 9.5 mm of coat — ideal for breeds that need a longer, fluffy finish like Poodles, Labradoodles, and Cocker Spaniels. It's a great starting blade if you're new to clipping and want to avoid cutting too short. Shop the Groom Ultra Edge #4F Blade →
#7F — The Workhorse Blade
The #7F blade is arguably the most versatile blade in any groomer's kit. At 3.2 mm, it's short enough for a neat all-over clip but long enough to avoid that "shaved" look. It's the go-to for Schnauzers, Cocker Spaniels, and many mixed breeds. Shop the Groom Ultra Edge #7F Blade →
#10 — The Detail Blade
The #10 blade cuts to 1.6 mm and is the standard choice for sanitary areas, paw pads, around the ears, and the face. Most groomers keep a #10 on a second clipper specifically for these sensitive zones. Shop the Groom Ultra Edge #10 Blade →
#30 — Close and Precise
At just 0.5 mm, the #30 blade is used for very close work — think surgical prep or extremely tight face trims. It requires a steady hand and is not recommended for general body clipping on pets. Shop the Groom Ultra Edge #30 Blade →
Which Blade Should You Start With?
If you're building your first blade kit, we recommend starting with a #7F for the body and a #10 for detail work. These two blades cover the majority of grooming situations for most breeds. Browse our full range of Pet Clipper Blades to find the right fit for your dog.
Don't Forget Blade Maintenance
Even the best blade dulls quickly without proper care. Always oil your blades before and after each use with a quality Clipper Blade Oil to reduce friction, prevent overheating, and extend blade life.