How much protein is in kidney beans?
Kidney beans has 7.1 g of protein per 1/2 cup (89 g) — that's 8 g per 100 g, or about 2.3 g per ounce. One 1/2 cup is roughly 14% of the 50 g Daily Value for protein.
USDA FoodData Central · red, canned, drained · FDC 174285
Protein & macros by portion
| Portion | Protein | Calories | Fat | Carbs |
|---|---|---|---|---|
| 1/2 cup (89 g) | 7.1 g | 110 | 1 g | 19.1 g |
| 100 g | 8 g | 124 | 1.1 g | 21.5 g |
| 1 oz (28 g) | 2.3 g | 35 | 0.3 g | 6.1 g |
Values computed from USDA per-100 g data (FDC 174285, SR Legacy). red, canned, drained.
A normal scoop of kidney beans is a 1/2 cup of the drained canned beans (89 g), and that gets you about 7.1 g of protein for roughly 110 calories. Bump it to a full cup (178 g) — a chili-bowl or main-dish portion — and you’re at about 14.2 g of protein. Per 100 g the figure is 8 g, which is honest but worth keeping in perspective: that’s a fraction of what an equal weight of chicken or tofu delivers. Kidney beans are a moderate plant protein, not a high-protein food, and the smart way to read this page is to look at what comes with the protein rather than the protein number alone.
Protein and fiber, working as a pair
Like all beans, the reason kidney beans punch above their modest protein line is fiber. At about 5.5 g per 100 g, a full cup brings close to 10 g of fiber alongside its ~14.2 g of protein — and that pairing is what makes them so filling and so useful in a meal. Protein and fiber both slow digestion and blunt the energy spike from the carbohydrates kidney beans also carry (about 21.5 g per 100 g), so a cup keeps you satisfied in a way the protein figure alone wouldn’t predict. They’re also very low in fat (around 1.1 g per 100 g, almost none of it saturated), cholesterol-free, and a source of iron and potassium. If you treat kidney beans as a fiber-rich carbohydrate that happens to bring a useful amount of protein, you’ll use them right.
Quality, and the famous fix
On protein quality, kidney beans have the usual legume limitation: their protein is incomplete, low in the amino acid methionine. The fix here is the most famous one in all of cooking — pair the beans with rice. Rice (like other grains) supplies the methionine the bean is short on, so a plate of rice and beans together covers all nine essential amino acids and counts as a complete protein. That’s not a nutritionist’s trick; it’s the reason rice and beans anchor cuisines from the Caribbean to Latin America to the American South. Across a varied day you don’t strictly have to combine them in the same meal, but it explains why kidney beans shine as a component rather than a standalone protein. One practical note on the canned version: it carries about 231 mg of sodium per 100 g straight from the tin, so draining and rinsing is worth the ten seconds.
For a fuller plate, it’s worth comparing kidney beans against the other legumes on this site — chickpeas, black beans, and lentils — all of which sit in the same moderate-protein, high-fiber band and slot into the same rice-and-beans logic. If you want to see how a serving of kidney beans fits into your day, our guide on how much protein per day walks through setting the target first.
Frequently Asked Questions
How much protein is in kidney beans?
About 7.1 g of protein in a 1/2 cup serving of canned, drained red kidney beans (89 g), which is 8 g per 100 g (USDA FDC 174285). A full cup (178 g) roughly doubles that to about 14.2 g of protein for around 221 calories — and brings a heavy dose of fiber along with it.
Are kidney beans a good protein source?
They're a moderate one, not a heavyweight. At 8 g per 100 g, kidney beans carry far less protein than meat or tofu on a gram-for-gram basis, so a 1/2 cup side of about 7.1 g won't move the needle much on its own. Where they earn their keep is the combination: a full cup delivers around 14.2 g of protein plus a big slug of fiber in the same scoop, which is what makes them genuinely useful in a plant-forward diet.
How much is a serving of kidney beans?
A standard serving is 1/2 cup of drained canned kidney beans (89 g, ~110 calories), a typical side or chili portion. A full cup (178 g) is closer to a main-dish serving and gets you to about 14.2 g of protein. Canned kidney beans also carry added sodium — around 231 mg per 100 g straight from the tin — so draining and rinsing cuts a good share of it.
Are kidney beans a complete protein?
No, not on their own. Like most legumes, kidney bean protein is incomplete — it's low in the amino acid methionine. The classic fix is famous: pair them with rice. Grains supply the methionine the bean is short on, so rice and beans together form a complete protein with all nine essential amino acids — which is exactly why that combo anchors so many cuisines.
What are kidney beans good for nutritionally?
Fiber is the headline — about 5.5 g per 100 g, which pairs with the protein to make kidney beans genuinely filling. They're also very low in fat (about 1.1 g per 100 g, almost no saturated), cholesterol-free, and supply iron, potassium, and complex carbohydrates for steady energy. The fiber-plus-protein combo, not the protein alone, is the real reason to keep a can on hand.
When was this data last verified?
2026-06-03, against USDA FoodData Central FDC 174285 (Beans, kidney, red, canned, drained solids; SR Legacy). We re-verify reference pages periodically and update when the underlying USDA entry changes.
Whole-food values are USDA reference data and are not assigned a Labelgrade — that score is for branded packaged products, where ingredients and added sugar/sodium actually vary. See our methodology and how much protein you need per day.