After reading too many disappointed groomings gone wrong, I thought I'd start a thread explaining the difference of blade sizes & how much hair it leaves. Please feel free to add any info.
10 leaves approximately 1/8" of hair on body
7F 1/4"
5F 1/2"
4F 3/4"
1" comb 1"
1 1/2" comb 1 1/2"
E comb 2"
The higher the #, the shorter the cut.
The 40 blade is used for surgical shaves & the paw pads.
The 30 blade is best for attaching combs, but the 40, 15, 10 can also be used.
The 10 blade is used for sanitary cuts & for severly matted areas that is to the skin.
The 7, 5, & 4 blades come in Skip Tooth & Full Tooth. Skip Tooth is mainly used to blend bulky lines & for terrier cuts. The Full Tooth has the letter F after the #: 7F. This is what the groomer widely uses to cut the pet's hair.
When talking to your groomer, be very specific. Write it down on a piece of paper if you have to.
It is best to tell the groomer how much hair you want to leave. There's always a chance that they can cut the hair shorter esp if they use a clipper vac system (usu mobile). So ask if they use this & if they do, tell them to go a blade or comb one size longer. If you request a 5F, ask them to use a 4F & so on.
Here's Momo w/a cut on his body w/a 5F:
IMG_1031.jpg 7F
IMG_1444.jpg You can see a difference in the cuts.
Momo has alot of thick, cottony hair. If Mimi, who has a fine silky hair had a cut w/a 7F, she'd look nekkid & bald.

She'd be better off having her length cut w/a scissor or if I wanted her short for the summer, maybe w/a comb. So please go according to your furbaby's hair. Happy Grooming everyone (hopefully)!