What do the blade size numbers mean?
Standard blade sizes work in reverse to what you might think. A #30 blade is a lot shorter than a #3 blade for example. The higher the number, the shorter the coat will be. To take the guesswork out, each blade (and comb attachment), tells you what length it will leave the coat (usually given in mm's).
The blade number does not tell you the coat length (so a 4 blade doesn't mean the coat will be 4mm, 14mm, or 4cm for example - a #4 is actually just under 1cm). There can also be small differences between brands in the same side blade. Wahl's 4 blade leaves the coat 8mm, Andis is 9.5mm, Geib is 9mm, and Laube is 9.6mm, but all are #4 blades.
A #5 blade - such as a 5F or 5FC - is a popular body length blade which leaves the coat around 6mm. A #3 (13mm) or #7 (3mm) might also be body length blades. Search our help section to find out the difference between F, FC and ST blades. All might be called body length, because ‘body length’ depends on breed, coat type, dog size and personal preference - so it's best to buy based on the mm's the blade or comb attachment leaves the coat, rather than what the breed standard says.
The description for every blade tells you the resulting coat length, but if you’re unsure, view our grooming guides, get a book like The Theory of 5, or watch YouTube videos for grooms you like the look of, and note down what the groomer uses.