Dog clipper blade sizes use an inverse numbering system where a #40 blade leaves the shortest cut (about 0.5mm) and a #1 blade leaves the longest (about 19mm), with the #10 blade as the standard for sanitary trims.
That small metal piece on your clipper determines everything — whether you get a smooth finish, a fluffy puppy cut, or a burnt patch from the wrong choice. The numbers seem backward (higher number = shorter cut), but the logic is consistent once you know the chart. The table below covers the US-standard detachable blades, from the delicate #40 used only on paw pads to the long #1 for show trims.
Understanding the Blade Numbering System
The industry standard runs from #40 (shortest) to #1 (longest), with “F” suffixes indicating a Finish blade that leaves a smoother surface than the standard “Skip” blade of the same number. A #7F and a #7 cut to the same 3.2mm length, but the #7F leaves a cleaner, blended look because its teeth sit closer together. Skip blades (no F) leave a slightly textured finish, which works well for blending matted coats during a shavedown.
All the lengths in this chart apply to detachable blade clippers — the kind where blades snap onto the head. Cordless mini clippers often use smaller proprietary blade sets that follow different sizing. For standard clippers, snap-on combs fit over #10, #15, #30, and #40 blades to add length without changing the blade.
Complete Blade Length & Use Chart
| Blade Size | Cut Length | Typical Use |
|---|---|---|
| #40 | 0.3–0.5mm (1/100″) | Surgical prep, show poodle feet/face, paw pads only |
| #30 | 0.5mm (1/50″) | Ultra-fine trims, between pads, used with snap-on combs |
| #15 | 1.2–1.8mm (3/64″) | Close poodle faces, clean feet, sensitive pads |
| #10 | 1.6–2mm (1/16″) | Sanitary trims, mat removal, poodle/cocker faces |
| #9 | 2mm (5/64″) | Smooth finish on sporting breed necks and bodies |
| #8½ | 2.8mm (7/64″) | Head, face, neck on sporting breeds and terriers |
| #7 / #7F | 3.2mm (1/8″) | Standard shavedown, body work on terriers and poodles |
| #5 | 6mm (1/4″) | “Short-but-not-shaved” look, good all-round short blade |
| #4 | 9.5mm (3/8″) | Short-but-fuzzy look, puppy cuts, sheepdogs |
| #3 | 12.7mm (1/2″) | Plush/puppy look, Lhasa and Shih Tzu bodies |
| #2 | 16mm (5/8″) | Longer cuts, often for terriers |
| #1 | 19mm (3/4″) | Show-type trims, long full-body coats |
| #0F | 22mm (7/8″) | Longer coats, suitable for some breeds |
Breed-Specific Blade Choices
Each breed standard calls for specific blade numbers. On pet poodles, the feet and pads get a #30 or #40 blade, while the face uses a #10 or #15. Show poodles take #40 or #50 on feet, face, and patterns, with body work done at #3 or #4. Terriers typically get body work with a #7 or #5, and face or head work with a #9 or #7F. For sporting breeds like Cocker and Springer Spaniels, the neck and body finish with a #9, while the head and face use #8½ or #7F. Lhasa Apsos and Shih Tzus needing a plush puppy look take a #3 or #3 3/4 over the body.
If you’re equipping your grooming kit for the first time, start with a set containing #4, #5, #7, and #10 blades, plus a spare set for sharpening rotation. Before buying, check our curated picks of the best clipper blades for dogs that hold edges well and fit most detachable clippers. Stainless steel versions resist rust and stay sharp longer than standard carbon steel.
Common Mistakes That Ruin The Cut
The most frequent error is using a #40 blade on general body coat — it causes skin burns, nicking, and bald patches. Going “against the grain” cuts hair shorter than the listed length (a #7 becomes 1/4″ instead of 1/8″), so always clip with the grain unless you intentionally want a shorter effect. Skipping coat prep — bathing and brushing out mats first — makes clippers snag, pull, and jam, which hurts the dog and dulls the blade. Watch blade temperature too: a hot blade burns skin fast. Stop if it feels warm and use a blade coolant.
FAQs
What is the difference between a #7 and a #7F blade?
Both cut to exactly 3.2mm (1/8″), but the #7F is a “Finish” blade with finer tooth spacing that leaves a smooth, blended surface. A standard #7 (Skip blade) has wider-spaced teeth that produce a slightly textured finish, which helps blend matted or uneven coats.
Can I use a #40 blade on my dog’s body?
Not unless you are highly experienced and deliberately doing surgical prep or show patterns. For body work, stay at #10 or higher.
Do these blade sizes work for cordless mini clippers?
Not usually. Cordless mini clippers often use smaller proprietary blade sets that follow different sizing conventions. The chart above applies to standard detachable blade clippers where the blade snaps off the clipper head.
References & Sources
- Revival Animal. “Dog Grooming Clipper Blade Chart: Size and Use.” Covers the full blade size chart with cut lengths and common use cases.
- PDGA (Professional Dog Groomers Association). “Dog Grooming Blade Length and Chart.” Provides industry-standard blade sizing and breed-specific recommendations.
Mo Maruf
I created WellFizz to bridge the gap between vague wellness advice and actionable solutions. My mission is simple: to decode the research and give you practical tools you can actually use.
Beyond the data, I am a passionate traveler. I believe that stepping away from the screen to explore new environments is essential for mental clarity and physical vitality.