Dog Grooming Blades Explained | Short, Safe Cuts by Number

For the full breakdown, see our best Dog Grooming Blades guide.

Whether you’re cleaning up paw pads or giving a full body clip, the number stamped on a detachable blade tells you exactly how short the cut will be. Lower numbers leave more coat; higher numbers cut closer to the skin. The trade-offs matter because the wrong blade can leave a choppy finish or irritate sensitive skin. Here’s what each size does and where it fits in a typical grooming session.

What The Blade Numbers Mean

Every detachable blade has a number that maps to a specific cutting length in fractions of an inch and millimeters. The chart below shows the standard sizes you’ll see on most brand charts, though exact millimeter equivalents can vary slightly by manufacturer.

Skip Tooth vs. Finishing Blades

Skip tooth blades have wider spacing between teeth and leave more coat behind, which helps them power through heavy or matted fur without snagging. Finishing blades have tighter teeth and produce a smoother, closer, more even cut. Many popular sizes come in both versions — 3/3F, 4/4F, 5/5F, and 7/7F — so you can pick based on coat condition.

For a matted or knotted coat, the skip tooth version is often the safer start. For a clean, polished finish on a well-brushed coat, the finishing blade gives that tidy look. If your dog’s coat is heavily tangled, don’t force a close blade through it; work out the mats first or start with a longer blade, then switch to a closer size for the final pass.

Which Blade For Which Job

Start here if you’re unsure.

For closer, more precise work, the #15 handles sensitive poodle feet, pads, and face on some breeds, while #30 and #40 are reserved for ultra-tight surgical or veterinary prep and poodle feet. Those very close blades cut at 0.5 mm or tighter, and casual at-home grooming on sensitive skin can easily cause irritation, so reach for them only when the job genuinely calls for that level of closeness.

For body clips, match the blade to coat length and the look you want:

• #7F — short body clips, knotted or matted coats
• #5F — medium body clips
• #4F — longer body clips
• #3F — longest standard body clip at roughly 1/2 inch

Compatibility And Common Mistakes

Blade numbers are not fully standardized across every brand chart. One source may list a slightly different millimeter equivalent for the same numbered blade, so always verify the specific brand’s chart before making breed-specific decisions. Wide blades, wide-tooth blades, and special variants like “T-84,” “Wide 10,” “30W,” and “15W” have different widths and uses than standard blades, so check what fits your clipper model.

Three mistakes cause most grooming problems. Confusing finishing blades with skip-tooth blades leaves an uneven result. Assuming numbers map identically across brands leads to surprise lengths. And forcing an ultra-close blade through a dense or matted coat risks nicks and pain for the dog. When in doubt, go longer and work down.