Course 09 · Nails · Lesson 1 of 12

How do dog nails grow, and what is the quick?

Published 29 October 2026 · Updated 29 October 2026 · About 5 minutes · General information only. This lesson does not diagnose or treat any condition.

Dog nails grow continuously from the base, near the toe, and are worn down naturally by walking on hard surfaces, though most pet dogs need regular trimming as well. Inside each nail is the quick, a core of living tissue that carries blood vessels and nerves. Trimming the hard, dead outer nail is painless when done correctly, but cutting into the quick causes pain and bleeding, which is why nail trimming is done in small amounts, with the quick in mind at every cut. Understanding growth, the quick, and how the quick changes with trimming frequency gives you the foundation for every later nail lesson.

How does a nail grow and wear?

A nail is made of a hard outer shell, similar in nature to a human nail, growing forward from the nail bed at the base. As it grows, the tip becomes longer, thicker and often more curved, and the nail may start to touch the ground, splay the toes, or catch on surfaces. Walking on pavement, paths and other hard ground files the tip naturally, which is why active dogs on hard surfaces often need less trimming than less active dogs, or dogs that walk mainly on grass and soft ground. Growth rate varies by dog, by age, by activity and by nail, with front nails often wearing differently from back nails, and dewclaws, where present, wearing very little because they do not touch the ground. Regular checking, rather than a fixed calendar alone, tells you when a nail needs attention.

What is the quick, and where is it?

The quick is the pink, living core inside the nail, containing blood vessels and a nerve. In a light nail, it is often visible as a pink shadow through the nail, ending before the tip. In a dark nail, it cannot be seen through the shell, and its position must be judged by shape, by the appearance of the cut surface, and by taking off very small amounts, as Lesson 5 explains. The quick grows forward as the nail grows, and it recedes gradually when nails are trimmed regularly in small amounts, which is why frequent, light trimming can slowly shorten a long quick over time. The quick is longer in a nail that has been left to grow, and shorter in a nail that is kept trimmed, so an overgrown nail cannot safely be cut back to a short length in one session.

How do nails differ across dogs?

Nails differ in colour, thickness, curve and hardness. Light nails show the quick clearly, dark nails hide it, and some dogs have a mix, with light and dark nails on the same paw. Thick nails, common in larger dogs, need a stronger trimmer or a grinder, and they can split if cut with a blunt tool. Thin nails, common in smaller or older dogs, can be trimmed with a smaller trimmer or a file, but they can also break if cut too close. Dewclaws, the extra nails higher on the leg, need checking because they do not wear down and can grow in a curve into the pad if neglected. Older dogs may have more brittle nails, and dogs with certain health conditions may have nails that grow unusually, crack or break, which needs veterinary assessment, not more aggressive trimming.

What does a healthy nail look like?

A healthy nail is smooth, without deep cracks, splits or flaking, and it is trimmed so the tip just clears the ground when the dog stands, without the toe splaying or the nail clicking loudly on a hard floor. The nail should follow the natural curve of the toe, without twisting, and the pad should be free from a nail growing into it. A nail that is too long changes how the dog stands and walks, puts pressure on the toe joints, and is more likely to snag, split or break. A nail that is cut too short, into the quick, bleeds and hurts, and can make the dog fear the next trim. The aim is a middle path: short enough to clear the ground and keep the toe comfortable, long enough to stay well clear of the quick, achieved in small, regular trims.

Use this check to judge nail length at home:

1. Watch the dog stand on a hard floor. Do the nails touch the ground or click loudly?
2. Look from the side. Does the nail curve down past the pad, or follow the toe line?
3. Look at each nail, including dewclaws, for cracks, splits or curling.
4. Feel the tip. Is it sharp and snagging, or smooth and blunt?
5. Note the quick position on light nails, and the cut surface guidance for dark nails.

If nails touch the ground, click loudly, or curl, they need a light trim, in small amounts, as the next lessons explain.

Stop and get help: when is a nail a vet problem, not a trim?

A nail is a vet problem when it is cracked, split to the base, bleeding that will not stop, infected, swollen, painful, growing into the pad, or when the toe itself is swollen, sore or deformed. It is also a vet problem when a nail breaks off, when a nail grows unusually, or when trimming causes severe pain or distress despite gentle handling. Do not try to cut a nail that is already damaged, do not pull a broken nail, and do not apply a product to a damaged nail unless a vet has advised it. Seek veterinary advice promptly for bleeding that will not stop, for a broken or torn nail, and for any sign of infection or pain. Regular trimming prevents many nail problems, but it does not treat a nail that is already injured or diseased, and knowing that boundary keeps a routine trim from becoming a painful mistake.

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