Grooming and coat
What do dog clipper blade numbers mean?
Last updated 23 September 2026 · How we write and check this
Short answer
Clipper blade numbers indicate how short a cut leaves the coat, with higher numbers cutting shorter. A number 10 blade leaves roughly 1.5 mm of hair, close to a kennel cut length, while a number 4 leaves closer to 9.5 mm, a much fuller length. Guard combs snap onto a blade to extend the cutting length further.
Reading the scale
The numbering runs opposite to what many first time owners expect: a number 40 blade, used mainly for surgical prep, leaves almost no hair, while a number 3 or 4 leaves a fuller, more visible length. Most pet grooming falls somewhere between a 7 and a 10 blade for a short, even trim.
How guard combs extend the range
A plastic guard comb clips over a standard blade, most often a 10, and adds extra length on top of the blade's own cut, which is how groomers achieve a range of lengths from one blade rather than owning a separate blade for every possible finish. Guards are labeled in millimeters or inches and typically add anywhere from 3 mm to over 2.5 cm.
Choosing the right length for your dog
Asking a groomer what blade or guard length they used on a cut you liked is the simplest way to request the same result next time, and writing it down avoids relying on memory or vague descriptions like short or medium at the next appointment.
Key takeaways
- Higher clipper blade numbers cut shorter, the opposite of what many owners first assume.
- Most everyday pet grooming uses blades in the 7 to 10 range.
- Guard combs snap onto a blade to add extra length, letting one blade produce several finishes.