Knife cut sizes: dice, julienne, brunoise and chiffonade (chart in mm and inches)
The three standard dice sizes are small dice, 6 mm (¼ in), medium dice, 12 mm (½ in) and large dice, about 19–20 mm (¾ in). A julienne is a 3 mm (⅛ in) square stick about 50 mm (2 in) long, and a chiffonade is a fine ribbon of rolled leaves. Knife cuts are a cooking control, not a decoration: pieces of the same size finish at the same moment. The dice covers anything that cooks in a pan or a pot, the julienne anything that must cook fast or stay crisp, and the chiffonade leaves. The full chart is below, with the grip and board setup that make the cuts possible.
Before the cuts: board and hands
Two things have to be right before size is even a question.
A board that cannot move. Wet a piece of kitchen paper or a thin cloth, wring it out, and lay it flat under the board. A board that slides is a board that puts your knuckles in the path of the blade. Check the board sits flat with no rock in it, and work with the board square to the front of the counter, not at an angle.
The claw. The guide hand holds the food with the fingertips curled back under the knuckles and the thumb tucked behind them. The flat of the blade rests lightly against the middle knuckles and rides along them. The knuckle, not the fingertip, is the part nearest the edge, and the knuckle is a stop rather than a target. The guide hand walks backwards in small steps and the knife never lifts higher than the knuckles.
Two habits that make the claw work rather than just look right:
- Keep the blade in contact with the knuckles for the whole cut. If the knife leaves the guide, you are cutting blind.
- Move the hand, not the knife. The width of each slice is set by how far back the guide hand steps, which is why even cuts are a guide-hand skill before they are a knife skill.
None of it works on a blunt blade, which skates off a curved surface instead of biting. If yours will not start a cut on tomato skin under its own weight, that is a whetstone job before it is a technique job.
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The size chart
These are the classical culinary dimensions, as taught with imperial measurements and converted here to metric. The figures below follow the standard set published by Rouxbe's knife-cuts reference.
| Cut | Metric | Classical imperial | Typical job |
|---|---|---|---|
| Brunoise | 3 × 3 × 3 mm | ⅛ × ⅛ × ⅛ in | Garnish, fine sofrito, anything that must disappear into a sauce |
| Small dice | 6 × 6 × 6 mm | ¼ × ¼ × ¼ in | Quick sautés, salsas, mirepoix for a short-cooked sauce |
| Medium dice | 12 × 12 × 12 mm | ½ × ½ × ½ in | Soups and stews of an hour or so |
| Large dice | about 19–20 mm cube | ¾ × ¾ × ¾ in | Roasting trays, long braises, stock vegetables |
| Batonnet | 6 × 6 mm, 50 mm long | ¼ × ¼ × 2 in | Chunky sticks; the stage before a small dice |
| Julienne | 3 × 3 mm, 50 mm long | ⅛ × ⅛ × 2 in | Stir-fries, slaws, raw garnish |
| Fine julienne | 1.5 × 1.5 mm, 50 mm long | ¹⁄₁₆ × ¹⁄₁₆ × 2 in | Fine garnish only |
| Paysanne | 12 × 12 × 3 mm | ½ × ½ × ⅛ in | Flat tiles for a broth or a light soup |
Two notes on reading that table honestly. The metric figures are conversions of imperial originals, so a 12 mm dice is really a half-inch dice at 12.7 mm; nobody is measuring, and a millimetre either way changes nothing. Lengths for julienne and batonnet are commonly given as 50 to 60 mm (2 to 2½ inches) rather than one fixed number, because the length is set by the vegetable you are working with as much as by the rule.
Chiffonade is not on the chart because it has no classical cube dimension. It is a ribbon cut, as fine as your edge will produce without bruising the leaf.
The dice, step by step
The sequence is the same at every size. Only the width of the cuts changes.
- Square it off. Cut a thin slice from one side so the vegetable can sit flat and cannot roll. Round things roll, and rolling is how the blade goes where you did not intend. Take a second slice off an adjacent face if you want clean edges.
- Flat slices. Slice the vegetable into flat slabs at your target thickness. For a 6 mm dice, that is 6 mm flat slices.
- Batonnet. Stack two or three flat slices, no more than you can keep steady under the claw, and cut down through the stack into sticks of the same width.
- Dice. Turn the sticks a quarter turn, gather them, and cross-cut at the same width. Three equal dimensions, three identical passes.
Flat slices, sticks, cubes. That is the whole method, and it scales from brunoise to a large roasting dice without changing.
The offcuts from squaring off are not waste. They go in a freezer bag for stock, where the shape does not matter because everything is strained out anyway.
[CHEF NOTE] Squaring off feels wasteful the first time you do it and it is the step that separates a fast prep cook from a slow one. Uneven, rolling vegetables force you to slow down for safety; a flat, stable block lets you cut at speed without thinking about your hand. The trim goes in the stock bag, so the yield loss is smaller than the time you save.
The julienne
A julienne is the dice sequence stopped one step early — flat slice, then stick, no cross-cut. Cut the flat slices thin, stack a manageable few, and slice down through the stack.
Where it earns its place is cooking rate. At 3 mm square, a carrot and a pepper reach doneness at nearly the same moment, which is what stops a stir-fry arriving as limp peppers next to raw carrot. Raw, the same cut is what makes a slaw pleasant to eat instead of a pile of shards.
Only stack what the claw can hold flat. Four flat slices that shift under the blade produce worse and more dangerous cuts than two that do not.
The chiffonade
This is for soft leaves: basil, mint, sage, sorrel, spinach. The enemy is bruising, because a crushed cut edge on basil goes black within minutes and tastes of it.
Stack the leaves, largest at the bottom, roll them into a tight cigar, and slice across into ribbons in one clean draw. Do not saw. A sawing stroke crushes as much leaf as it cuts. Let the length of the blade do the work in a single movement, and use the sharpest knife you own.
Cut leaves last, immediately before they are needed. A chiffonade that sits on the board for ten minutes has already lost most of what you cut it for.
Why the size actually matters
| Situation | What goes wrong with uneven cuts | What even cuts give you |
|---|---|---|
| Onions softening in a pan | Small pieces colour while large ones are still raw | A base that softens evenly with no scorched flecks |
| A stew | Small dice collapse to mush, large dice stay firm | One texture across the pot |
| A stir-fry | Thick pieces go in raw at the end | Everything is done at once |
| A roasting tray | Small pieces burn before the big ones colour | One tray, one timing |
| A blanching pot | Pieces come out at different doneness | One timed lift for the whole batch |
That last row is why cut size is worth fixing before a prep session rather than during one. Both a sweated onion base and a tray of blanched and shocked vegetables are single-timing processes: one lift, one finish. They only work if everything in the pan is the same size.
Practice that actually improves the cut
Buy three onions and dice all three back to back, aiming at 6 mm. Do not judge the first one. Compare the third against the first — the difference is almost always in the guide hand, not the knife hand. Then check the pan: an even dice browns as one thing, which is the only proof that matters.
A carrot practice exercise you can check
Use one firm carrot to practise two related cuts before moving to onions or soft leaves. This is a practice plan, not a timed test or a claim about a measured kitchen trial.
- Make a stable flat face, then cut a short block into 6 mm flat slices. Keep the offcuts separate.
- Cut a few flat slices into 6 mm sticks. Cross-cut those sticks at 6 mm to make small dice.
- With another block, repeat at 3 mm to make julienne. Leave some as sticks and cross-cut a few at 3 mm to make brunoise.
- Put the knife down before checking. Pick ten pieces from different parts of the batch and compare their thickness against a ruler on a clean surface. Look for wedges, tapered sticks and cubes with one long side; those show which pass needs attention.
| What you see | What to check on the next batch |
|---|---|
| Sticks taper from end to end | Flat slices are uneven, or the blade is travelling at an angle |
| Cubes have one long side | The spacing of the final cross-cuts differs from the stick width |
| The bottom of the stack spreads | Reduce the stack and use a flat, stable face |
| Pieces crush or tear | Check the edge and slow down rather than pushing harder |
Aim for consistent pieces before speed. Keep a note of the target size and the problem you corrected; do not mix the 3 mm and 6 mm batches into a dish that needs one cooking time. Sound offcuts can go into a suitable stock batch, rather than being counted as finished dice.
Turn the cut into a prep instruction
A useful spec names the ingredient, finished quantity, cut and destination: carrot — 500 g prepared weight — 3 × 3 mm julienne, about 50 mm long — slaw. That is an illustrative instruction, not a yield result. Weigh after trimming when the recipe calls for prepared weight; buying 500 g of whole carrot does not guarantee 500 g of finished sticks.
Write the spec in the notes column of the free kitchen prep sheet. Use the yield calculator with your own weighed starting and finished amounts if you need to translate a prepared quantity into a purchase quantity.
Knife cut questions
What are the three sizes of dice?
Small dice is 6 mm (¼ in), medium dice 12 mm (½ in) and large dice about 19–20 mm (¾ in). Brunoise, at 3 mm (⅛ in), is sometimes counted as a fourth, finer dice.
What size is a julienne?
A standard julienne is 3 × 3 mm (⅛ × ⅛ in) and about 50 mm (2 in) long. A fine julienne is half the width, 1.5 mm (¹⁄₁₆ in) square.
What is the difference between a chiffonade and a julienne?
A julienne is a matchstick cut from a firm vegetable such as carrot or pepper. A chiffonade is a ribbon cut from soft leaves that have been stacked and rolled, and it has no fixed size: it is as fine as the edge allows without bruising.
What size is a brunoise?
A 3 mm (⅛ in) cube. It is a julienne turned a quarter turn and cross-cut at the same width.
How do you keep a dice even?
Square the vegetable off, cut flat slices at the target width, stack only what the claw can hold flat, and move the guide hand back the same distance every time.
How should a cut size be written on a prep list?
Write the size, not just the cut: "onion, 6 mm dice" rather than "onion, diced", so every cook on the section produces the same piece. The free kitchen prep sheet template on ChefSums, this site's sister project, has a notes column for exactly that.
The kit for this job. A 20 cm chef's knife and an end-grain board that stays put. Affiliate links; the full list is on The Kit.
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