How much potassium is in onion?

161 milligrams of potassium in 1 medium (2-1/2 inch across)

Potassium in other portions of onion
Portion	Potassium
1 cup, chopped	234 milligrams of potassium in 1 cup, chopped
1 cup, sliced	168 milligrams of potassium in 1 cup, sliced
1 tablespoon chopped	15 milligrams of potassium in 1 tablespoon chopped
1 large	219 milligrams of potassium in 1 large
1 slice, large (1/4 inch thick)	55 milligrams of potassium in 1 slice, large (1/4 inch thick)
1 slice, medium (1/8 inch thick)	20 milligrams of potassium in 1 slice, medium (1/8 inch thick)
1 small	102 milligrams of potassium in 1 small
1 slice, thin	13 milligrams of potassium in 1 slice, thin
10 rings	88 milligrams of potassium in 10 rings
100 g	146 milligrams of potassium in 100 g

See everything in a serving of Onion, raw

Where these numbers come from

USDA FoodData Central, SR Legacy, record 170000. The source describes it as: Onions, raw.

U.S. Department of Agriculture, Agricultural Research Service, Beltsville Human Nutrition Research Center. FoodData Central. [Internet]. [cited 11 October 2026]. Available from https://fdc.nal.usda.gov/. Releases used: Foundation Foods, April 2026; SR Legacy, April 2018; Survey Foods (FNDDS 2021-2023), October 2024.

Data built on 11 October 2026 (data-2026-10-11).