What grit numbers mean
Grit number refers to the size of the abrasive particles on the file surface. The number is based on mesh size — how many holes per square inch a mesh would need to pass those particles through. A higher number = smaller particles = finer file. A lower number = larger particles = coarser file.
The practical implication: a 100-grit file removes material quickly and aggressively; a 240-grit file smooths and polishes. Choosing the wrong grit means either failing to remove what needs removing, or removing too much.
Nail file grit chart
| Grit | Abrasiveness | Typical use |
|---|---|---|
| 60–80 | Very coarse | Heavy duty product removal; rarely used in salon settings |
| 100 | Coarse | Shaping hard gel extensions, acrylic; NOT for natural nails |
| 120–150 | Medium-coarse | Shaping enhancements, removing gel polish from extensions |
| 180 | Medium | Natural nail shaping; refining gel/acrylic surface; most-used grit |
| 240 | Fine | Final smoothing of product surface; natural nail prep; sealing edges |
| 280–320 | Extra fine | Finishing buffer for product; removes minor scratches |
| 400–600 | Ultra fine | Polishing natural nail; high-gloss finishing |
| 1000–4000 | Buffing pads | Multi-step shine buff for natural or product surface |
File types explained
| File type | Construction | Best for | Hygiene |
|---|---|---|---|
| Emery board | Paper / cardboard core with abrasive coating | Natural nails; disposable per client | Single-use (cannot be sterilised) |
| Cushion / foam file | Foam core, more flexibility | Natural nail shaping; gentle use | Single-use preferred; some can be sanitised |
| Glass / crystal file | Tempered glass surface | Natural nails; seals nail edge cleanly | Can be washed with soap + disinfected; reusable |
| Metal file | Solid metal | Durable; long-lasting | Can be autoclave-sterilised; reusable |
| Buffer block | Multi-sided foam/sponge | Shine buffing; finishing | Single-use in professional settings |
Which grit to use for each task
| Task | Grit to use |
|---|---|
| Shape natural nail | 180–240 grit |
| Seal and smooth natural nail edge | 240–280 grit or glass file |
| Buff natural nail before gel application | 180–220 grit (remove shine only) |
| Shape hard gel extension | 100–150 grit |
| Shape acrylic extension | 100–150 grit |
| Refine gel/acrylic surface | 180–240 grit |
| Final surface smoothing before top coat | 240–320 grit |
| Buff to high shine (product or natural) | 400–600 grit buffer; then 1000+ if going shine-only |
| Remove shine from gel for infill | 180 grit lightly over existing product |
File hygiene and replacement
✓ File hygiene checklist
- ✓Use disposable emery boards and buffers — replace between clients without exception
- ✓Reusable files (glass, metal): wash with soap and water after each client, then disinfect
- ✓Metal files: autoclave-safe — sterilise regularly if your setup allows
- ✓Never use a natural nail file on extension/product (or vice versa)
- ✓Label file sets for natural nails vs. product to avoid cross-use
- ✓Replace files when they feel smooth or take more passes than usual to achieve the same result
- ✓A file that sheds abrasive particles has degraded — replace immediately
For e-file/drill bit equivalents: nail drill bits explained. For how file choice affects prep quality: nail prep guide for better retention.
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Start free →Frequently asked questions
Can you use the same nail file on natural nails and gel/acrylic?
You can physically use the same file, but you shouldn't. Files used on extensions accumulate product particles and lose abrasiveness. More importantly, a file appropriate for acrylic (100-grit) would badly damage natural nails. Keep separate files for natural nail prep and product work — and replace or disinfect between clients.
What grit nail file should a beginner nail tech use on natural nails?
180-grit is the most versatile starting point for natural nails — firm enough to file and shape, gentle enough not to damage. Many experienced nail techs use 180-grit as their primary natural nail file and only go coarser for specific extension prep tasks.
How often should nail files be replaced?
A file loses abrasiveness with use and cannot be fully restored. Replace files regularly — most professionals use disposable files and replace them between clients for sanitation reasons. Reusable files (crystal, glass, metal) can be disinfected between clients. A file that feels smooth or requires more passes than usual is past its effective life.
