Not every recipe needs the precision of a fine dice. Soups, stocks, sautes, and anything that cooks down for a while just need the onion broken into rough, bite-sized pieces fast, which is exactly what chopping is for.
Chopping trades the tight grid spacing of dicing for speed: fewer cuts, wider spacing, and a rocking motion at the end that breaks the onion into pieces without worrying about uniform size. It's the technique to reach for when you're prepping for volume, not precision.
This guide covers the faster cutting pattern, when to reach for it instead of a fine dice, and the mistakes that turn a quick chop into a slippery mess.
What You'll Need
- Chef's knife — The same 8-inch chef's knife used for dicing works here. The rocking motion at the end of this technique relies on a knife with a curved blade profile.
- Stable cutting board — Chopping involves more knife pressure and a faster pace than dicing, so a board that can shift is a real risk. A ROO Mat underneath keeps the board anchored through the rocking cuts.
- Bowl for scraps — A place for the skin and root end that isn't the cutting board itself.
How to Chop an Onion, Step by Step
Trim the stem, keep the root
Slice off the stem end and leave the root intact, exactly as you would for dicing. The root still does the job of holding the onion together for the next few cuts.
Peel and halve
Peel the skin away, then stand the onion on its flat end and cut straight through the root to create two halves.
Make wide horizontal cuts
Lay a half flat and make 2 to 3 horizontal cuts toward the root, spaced wider apart than you would for a fine dice, stopping just short of the root.
Make wide vertical cuts
Cut vertically down through the onion, again with wider spacing than a dice would use, stopping short of the root.
Rock-chop crosswise
Turn the knife perpendicular and rock it through the onion in a smooth back-and-forth motion, letting the pieces fall away in rougher, larger chunks than a dice produces.
Finish and discard the root
Trim away the last bit of root holding everything together and toss it with the skin into your scrap bowl or pouch.
Photo by RDNE Stock project on Pexels
Upgrade Your Prep: Get the ROO Bundle
ROO is a silicone mat that sits under your cutting board. It grips smooth countertops so the board never slides, and its built-in 7-cup pouch catches peels and trimmings as you cut. The Bundle includes the mat, a rubberwood board, and a reusable storage bag. $54.99.
Shop the ROO Bundle →Common Mistakes to Avoid
Chopping uses wider spacing and a faster rocking motion specifically because precision isn't the goal, so trying to make every piece identical just slows you down without any real benefit for a soup or stock.
Fully lifting the blade between each cut is slower and less controlled than keeping the tip anchored and rocking the heel, which is the whole point of the technique.
If a recipe just needs onion to melt into a sauce or stock, chopping it too finely wastes time you don't need to spend, since it'll break down either way during cooking.
The faster pace of chopping means more force behind each cut, and a board that slides even slightly becomes a real safety issue.
Upgrade Your Prep Workflow: The ROO Bundle
Chopping moves faster than dicing, which means more force and less margin for error if your board isn't locked down. The ROO Bundle's silicone mat grips the countertop so the board stays exactly where you put it through every rocking cut, and the scrap pouch keeps peels and root ends out from underfoot.
Upgrade Your Prep Workflow: Get the ROO Bundle
Chop faster with a board that stays put through every rocking cut.
Check out the ROO Bundle →Frequently Asked Questions
What's the actual difference between chopping and dicing an onion?
Dicing uses tight, evenly spaced grid cuts for uniform little cubes, while chopping uses wider spacing and a faster rocking motion for rougher, less precise pieces. Chopping is faster; dicing is more consistent.
When should I chop instead of dice?
Chop for anything that cooks down over time, like soups, stocks, braises, and sauces, where the onion will break apart anyway and exact size doesn't affect the final dish.
Is chopping an onion faster than dicing it?
Yes, noticeably. The wider cut spacing and rocking motion at the end mean fewer total cuts and less time spent lining up precise grid spacing.
Can I use the same knife for chopping and dicing?
Yes, a standard 8-inch chef's knife handles both techniques well. The curved blade profile that makes rock-chopping efficient is the same profile that works for a fine dice.
Why do my chopped onion pieces come out uneven in size?
Some size variation is normal and expected with chopping, since the whole point is speed over precision. If the pieces are wildly inconsistent, slow down slightly on the rocking motion rather than trying to force a dice-level result.
Chopping an onion is dicing's faster, less fussy sibling: same basic setup, wider cuts, and a rocking finish that trades precision for speed. Reach for it anytime the onion is headed into a pot to cook down, and save the fine grid method for dishes where the dice itself matters.