Whetstone grits for kitchen knives, explained by job
The grit number is a grain size
Sharpening stones come in a wide range of grits, and the grade refers to the size of the abrasive particles in the stone (Wikipedia: Whetstone). Lower numbers are coarser. Shapton, a Japanese manufacturer, publishes actual grain sizes for one of its lines on its own site: its #320 stone is listed at 40 micron and its #1000 at 11 micron, down through #2000 (6 micron), #3000 (4), #4000 (3), #6000 (2) and #8000 (1) (Shapton). Those figures are for that line only; other makers' numbers are not directly comparable, which is one reason a #1000 from one brand can cut differently from another's.
What each band is for
| Grit band | Job | Signs you need it |
|---|---|---|
| ~#200–#400 | Repair: remove chips, reshape a damaged edge | Visible nicks; a dent you can see or feel with a fingernail |
| ~#800–#1500 | Establish the edge on a dull knife | Knife slips on a tomato skin; edge is rounded |
| ~#2000–#4000 | Refine what the working stone made | Edge cuts but feels toothy or scratchy |
| ~#5000–#8000+ | Polish for push-cutting clean surfaces | Edge is already good and you want the last step |
The bands are typical use, not a rule, and the exact numbers shift by manufacturer.
How many stones do you actually need?
- One stone: a combination block (for example 1000/6000). It covers the working and finishing steps, but not repairs.
- Two stones: a medium (#1000-class) and a finer stone. This is the practical set for most home kitchens.
- Three stones plus flattening: add a coarse stone for repairs and a flattening stone. Only worth it if you own several knives or ones with damage.
Water stones and oil stones are different systems
Whetstones are often used with a cutting fluid to carry away swarf; stones used with water are often called water stones, those used with oil, oil stones (Wikipedia). Do not switch a stone from one to the other: the fluid you start with stays with that stone. Buy stones for the fluid you plan to use.
Honing versus sharpening
A honing steel realigns an edge; it does not remove much metal. Sharpening on a stone does. If a knife is dull, honing will not fix it (Kitchen knife, Wikipedia). Use a steel between sharpenings, and the stone when honing stops helping.
What to avoid
- Skipping the flattening stone. A dished stone changes the angle you present the edge at. Flatten as the stone wears.
- Buying a fine stone first. A #6000 stone will not fix a dull edge, and beginners often conclude the stone is defective.
- Assuming the number is universal. Compare grit sizes within one brand's line, not across brands.
- Trusting a promise of "10-minute" sharpening. Time depends entirely on the starting edge.
Honest limits of this guide
Related: Japanese kitchen tools covers the other tools that go with a good knife.