Nail files and buffers look alike, but the number printed on them changes everything. That number is the grit. The wrong grit is one of the most common causes of peeling, splitting nails, because a file that is too coarse tears the layers of the nail instead of smoothing them.
What grit means
Grit is the number of abrasive particles in a given area of the file.
- A low number is coarse. Fewer, larger particles remove material quickly.
- A high number is fine. More, smaller particles smooth and polish.
Grit chart
| Grit | Coarseness | Use |
|---|---|---|
| 80 to 100 | Coarse | Shortening and shaping acrylic or hard gel extensions only |
| 120 to 150 | Medium | Artificial nails; thick toenails |
| 180 | Medium-fine | Shaping strong natural nails; refining artificial nails |
| 240 | Fine | Shaping natural nails, especially thin or weak ones |
| 280 to 600 | Very fine | Smoothing the edge; light buffing of ridges |
| 900 to 4000 | Ultra fine | Polishing to a shine |
For natural fingernails, stay at 180 or higher. For thin, peeling or brittle nails, use 240.
Many files have a different grit on each side, shown as two numbers, such as 180/240.
File materials
| Type | Pros | Cons |
|---|---|---|
| Emery board (cardboard core) | Cheap, gentle, widely available | Wears out quickly; cannot be washed |
| Cushioned or foam file | Flexible, comfortable; many grits | Limited life; some can be washed |
| Glass or crystal file | Fine, even surface; seals the edge; washable; long-lasting | Breaks if dropped; slower for removing length |
| Ceramic file | Fine and gentle | Slow |
| Metal file | Durable | Often too harsh; can cause splitting |
A glass file or a 240-grit board is the kindest choice for natural nails. Etched glass keeps its texture for years, whereas cheaper coated glass wears smooth.
File shapes
- Straight boards are for general shaping.
- Banana or half-moon files follow the cuticle line and are used mostly on enhancements.
- Block buffers are for the surface of the nail.
Buffers
Buffers smooth and shine the surface of the nail plate. A four-sided block usually works in stages:
- File (coarsest side): for the free edge only.
- Smooth: reduces ridges.
- Buff: refines the surface.
- Shine: polishes to a gloss.
How to buff safely
- Use the gentlest sides on the nail surface.
- Make a few light strokes in one direction or in an X pattern. Do not rub back and forth quickly, which creates heat.
- Buff no more than once or twice a month.
- Stop if the nail feels warm or tender.
Each pass removes a thin layer of nail. Too much buffing leaves nails thin, flexible and sensitive. If you have ridges, a ridge-filling base coat is safer than buffing them flat. See Nail Ridges: What They Can Mean.
Using a file correctly
- File dry nails.
- Hold the file at a slight angle under the edge.
- Work from the side to the center in one direction.
- Finish with a fine grit to seal the tip.
How to File and Shape Your Nails explains shaping step by step.
What to buy
| Your nails | A good choice |
|---|---|
| Healthy natural nails | 180/240 board, or a glass file |
| Thin, peeling or brittle nails | 240 grit or glass only; skip buffing |
| Thick toenails | 100/180 board, plus clippers |
| Acrylic or hard gel extensions | 100/180 for shaping, 240 to refine |
| A shine without polish | A four-way buffer, used sparingly |
Care and replacement
- Tap or brush dust off after use.
- Wash glass, metal and washable files with soap and water, and let them dry.
- Replace emery boards and foam buffers when they look worn or dirty. They cannot be disinfected properly.
- Do not share files. See How to Clean and Store Nail Tools.
For clippers and scissors, see Nail Clippers vs Scissors: Which Tool Fits Your Needs?. If your nails split easily, read Brittle Nails: Causes and Everyday Care Tips.
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Frequently asked questions
What grit nail file is best for natural nails?
A fine grit of 180 to 240. Use 240 if your nails are thin, weak or peeling.
Are glass nail files better?
For natural nails, usually yes. They have a fine, even surface that leaves a smooth, sealed edge, and they can be washed.
How often should I buff my nails?
No more than once or twice a month, with light strokes. Frequent buffing thins the nail plate.