Best Knife to Cut Onions

We'd steer cooks who mostly want clean, thin slices toward this serrated knife, which is built for produce with a tough skin and a soft middle. Onions fit that description once the papery layer is off, and owners report that it also slices shallots and scallions finely, along with garlic.

The stainless blade is light (0.09 pounds on the spec sheet) and the textured handle is made to be non-slip and balanced. Owners report that the edge stays sharp through regular use and that it comes through repeated dishwasher cycles without rusting; a common complaint is that the blade feels a little flimsy. The pointed tip is a bonus on tomatoes, where it lifts out seeds.

This is not a knife at all, which is why we'd pair it with any blade on this page rather than treat it as a replacement. Stainless tines sink into the onion, and the wide plastic handle gives you something sturdy to hold while the knife works through the slices. Beside a thin slicer like the Omesata Tomato Knife, it keeps the produce steady while the blade does the cutting.

Owners report that it holds onions, other vegetables and meat firmly in place, feels sturdy, and keeps hands clear of the blade, which they find especially useful while knife skills are still developing. The tines can also double for tenderizing meat, and the tool is dishwasher safe.

If we had to hand one knife to a first-time buyer for onion work, this is where we'd start. Santoku means three virtues, and the maker lists onions among its target jobs; the hollow edge adds small scallops that keep wet slices from clinging to the blade.

Owners report that it takes and holds an edge, and they describe it as light and well balanced, with a handle that is comfortable for chopping vegetables. At 0.4 pounds it sits well below the Zwilling Pro Santoku Knife 5.5 Inch, which weighs 0.7 pounds, so this Classic is the one we'd choose when wrist fatigue is the worry. The fully forged construction and triple-rivet handle add durability, the blade is stain and rust free, and a lifetime warranty against manufacturer's defects comes with it.

At 5.5 inches this is the shortest santoku of the group, which makes it quick to maneuver on a board of smaller onions or shallots. The blade is forged from a single piece of high-carbon stainless steel with an ice-hardened finish, and the maker positions it for lasting sharpness under heavy daily use.

Owners report that it holds an edge, cuts smoothly, and feels well balanced without being heavy, and they say the curved bolster nudges the hand into a proper grip. Durability is a recurring theme, with owners expecting it to last for years. Cooks who prefer the longer reach of the Zwilling J.A. Henckels Classic Santoku Knife 7-Inch will find this one more compact, while those wanting a sturdier full-tang feel get it here at 0.7 pounds.

This is the santoku for cooks who dislike wooden or riveted handles: blade and handle are one piece of stainless steel with no gaps where residue can collect. The hollow scallops help wet onion slices release instead of clinging, and the 0.1-inch blade suits clean cuts through skins and layers. That spine weight also helps with dense vegetables, a trait that matters just as much when choosing the best knife to cut potatoes.

Owners report that it is razor sharp out of the box and keeps its edge, slicing through vegetables and bread, and that it feels light and balanced without tiring smaller hands; they also say it has held up in the dishwasher. Cooks comparing it with the Paudin Nakiri Knife 7" will notice the handle difference: pakkawood there, all steel here, which makes this one the easier choice when dishwasher cleanup matters.

We see this as the specialty pick of the lineup: a cleaver first, with an 18-degree double-bevel edge in German high-carbon stainless steel and a seamless full-tang steel handle. For onions it brings width and mass, and the broad blade also works as a scoop to carry chopped pieces to the pan. Set beside the Zwilling J.A. Henckels Classic Santoku Knife 7-Inch at 0.4 pounds, its 1.12 pounds is a very different feel in hand.

Owners report that it stays sharp, cuts cleanly through roasts and steaks, and has a grippy handle that doesn't slip; a common complaint is that the rounded handle can feel unsteady and a little handle-heavy until you adjust. Hand washing is recommended to protect the edge. Because of its size and weight, we'd choose it for cooks with larger hands or those who also break down meat.

A nakiri is the vegetable specialist in this group: the flat edge meets the board along its whole length, so a push-cut goes straight through an onion without the rocking motion a curved blade needs. That matches how owners describe it, with fast, even dicing of onions, squash and sweet potato. Cooks used to dicing with a santoku such as the Imarku Santoku Knife 7 Inch will find the flat profile the main change, along with the pakkawood handle.

The steel is 5Cr15Mov at 56+ hardness, and the waved pattern is meant to cut food friction. Owners report that it arrives very sharp, feels light and comfortable, and is easy to maintain. A common complaint concerns how the steel copes with very dense produce, and owners advise hand washing and drying right away, so this is not a dishwasher knife. It is also meant for vegetables and soft foods rather than bones or anything frozen.