Onion substitute in recipes: the ratios that work
Extension-published equivalents for one small onion, plus shallot, leek, scallion, fennel, celery and asafoetida ratios, which swaps work raw versus cooked, and when no substitute will do.
For 1 small onion, use 1/4 cup chopped fresh onion, 1 to 2 tablespoons instant minced onion, 1 1/3 teaspoons onion salt, or 1 teaspoon onion powder. NDSU Extension and Colorado State Extension both publish that same set of equivalents. If you would rather cook with a vegetable than a jar, shallots swap by chopped volume, and 2 to 3 small shallots cover 1 small onion.
Which swap works depends on whether the onion gets cooked. America's Test Kitchen traded onion and shallot at equal volume and found it fine in cooked dishes, while raw the onion tastes much sharper than the shallot it stood in for. Run it the other direction and the same rule holds, so shallots in a raw salsa or salad come out milder and sweeter than the onion the recipe wanted.
Onion substitute ratios at a glance
| Substitute | Ratio | Best for | Watch out |
|---|---|---|---|
| Onion powder | 1 tsp = 1 small onion = 1/4 cup chopped fresh | Meatloaf, burgers, dressings, dry rubs | About twelve times the strength of chopped fresh onion |
| Instant minced onion | 1 to 2 Tbsp = 1 small onion | Soups, meatloaf, dips, dry mixes | Rehydrate 10 minutes in the recipe's liquid first |
| Onion salt | 1 1/3 tsp = 1 small onion | Seasoning blends, rubs | Pull back the salt elsewhere in the recipe |
| Shallots | Same chopped volume, or 2 to 3 small shallots per small onion | Pan sauces, vinaigrettes, sautes, roasts | Sweeter and milder than yellow onion |
| Leeks, white and light green only | About 1:1 by volume, chopped | Soups, sautes, braises, quiche | Grit hides in the layers; dark tops are too tough |
| Scallions | About 1:1 by volume for the white parts | Cooked and raw dishes, green tops raw as a finisher | Milder, closer to shallot than to yellow onion |
| Fennel bulb | About 1:1 by volume, sliced | Caramelized or sauteed dishes, braises, roasts | Cook it down. Raw fennel tastes of anise |
| Celery | About 1:1 by volume, diced | Raw dishes and mirepoix-style bases | Keeps its texture instead of melting away |
| Asafoetida (hing) | A pinch, then add up | Low-FODMAP cooking, Indian dishes, allium-free households | Far stronger than onion, acrid if overdone |
How to swap onion in a recipe
- Convert the recipe to chopped volume. One small onion is about 1/4 cup chopped, per NDSU and Colorado State. One pound gives 2 to 2 1/2 cups chopped, per Mississippi State Extension.
- Sort the dish into raw or cooked. Cooked dishes take almost anything above. Raw dishes want celery, scallions or shallots, cut small.
- Measure the dried forms. Onion powder is about twelve times the strength of chopped fresh onion by volume, so a heavy hand ruins the dish.
- Bloom or rehydrate before the rest goes in. Onion powder wants hot fat. Instant minced onion wants 10 minutes in the recipe's liquid.
- Cut fresh alternatives the size the onion would have been. Shallot, leek and fennel cook faster than a big dice of onion.
- Fix the salt if you used onion salt. It brings its own, so take that much out of the recipe's salt.
What changes when you swap out onion
Shallots, leeks and scallions all taste sweeter and gentler than yellow onion, so a dish built on onion bite comes out softer. The Kitchn describes leeks as almost melting into soups and sautes, welcome in a chowder and less so in a chunky stew. Celery holds its shape, so you notice it in every bite. Fennel loses its anise note once it caramelizes, though raw in a salad it still tastes like licorice.
Onion powder and instant minced onion carry flavor and no bulk. In a meatloaf that is an improvement. In a stir fry you lose an ingredient's worth of volume, so add another vegetable.
When not to substitute for onion
Long, slow cooking is where the substitutes run out. Onion contributes sugar for browning and body from its pectin, and neither shows up in a spoonful of powder. French onion soup and a slow ragu want real onion, so buy some or cook something else.
If you cannot eat onion at all
Shallots, leeks and scallions are all alliums, so none of them are safe for an onion allergy. Onion salt, onion powder and instant minced onion are onion too. For a true allergy or a low-FODMAP diet, build the bulk from fennel bulb or celery in cooked dishes and add a pinch of asafoetida bloomed in hot oil or ghee. Raw, lean on celery, because fennel keeps tasting of anise until it cooks down. Tasting Table calls asafoetida the standard alternative for low-FODMAP cooks who have cut garlic and onion. It is much stronger than onion, so start with less than you think.
Related pantry swaps beyond onion
Our ingredient substitution chart collects the pantry ratios on one printable page, the fresh to dried herb conversion chart does the same for herbs, and fresh vs frozen vs canned substitution ratios covers what changes when you reach into the freezer. If you are short on something else entirely, walnuts instead of pine nuts in pesto is the cheapest swap on that list.
Find the onion swap you already own
Most onion substitutions start with opening the fridge and finding the onion gone soft. Well Stockd's substitution engine suggests swaps from what is already in your kitchen when a recipe calls for something you are out of. Frozen and canned forms count, and you can reject any form you never want suggested. More on that side in our guides to tracking food expiration dates and pantry inventory apps.
Onion substitute questions
How much onion powder equals one onion?
One teaspoon of onion powder equals one small onion, per NDSU and Colorado State Extension. Mississippi State Extension puts a full tablespoon at one medium onion, which lines up.
Can I use shallots instead of onions?
Yes. In cooked dishes, use the same chopped volume and cut the pieces to the same size. By unit, 2 to 3 small shallots replace 1 small onion. Raw, the onion tastes noticeably sharper.
How do I make raw onion less sharp?
Soak the sliced onion in ice water for 10 minutes. America's Test Kitchen uses that soak to make raw onion behave more like a shallot.
What can I use if I am allergic to onions?
Fennel bulb and celery for the bulk in cooked dishes, plus a pinch of asafoetida bloomed in hot oil for the savory allium note. Shallots, leeks and scallions are all onions and are not safe swaps.
Sources: NDSU Extension FN198, Colorado State Extension Fact Sheet 9.329, Mississippi State Extension, America's Test Kitchen, The Kitchn on shallot substitutes, The Kitchn on onion substitutes, Tasting Table.