Most adults need 1,000 mg of calcium a day, and you can reach it without dairy. The easiest sources are calcium-set tofu, fortified soy or almond milk, low-oxalate greens such as collards, kale and bok choy, and canned sardines or salmon eaten with the bones.
The catch: the milligrams on a label aren't what your body absorbs. Some plant calcium is absorbed better than milk's, and some, like spinach's, barely at all.
Key takeaways
- Target: 1,000 mg a day for most adults, 1,200 mg for women over 50 and everyone over 70.
- Best sources: half a cup of calcium-set tofu has 434-861 mg, a cup of fortified soy milk about 300 mg, and a cup of cooked collards 268 mg.
- Absorption: kale's calcium was absorbed at 41% versus 32% for milk in one study. Spinach's was absorbed at only about 5%.
- Read labels: tofu and plant milk calcium varies by brand. A label's %DV is a share of 1,300 mg.
- Supplements: only to fill a gap, no more than 500 mg at a time.
How much calcium do you need a day?
| Age group | Daily need (mg) | Upper limit (mg) |
|---|---|---|
| Teens 9-18 | 1,300 | 3,000 |
| Adults 19-50 | 1,000 | 2,500 |
| Men 51-70 | 1,000 | 2,000 |
| Women 51-70 | 1,200 | 2,000 |
| Adults 71+ | 1,200 | 2,000 |
| Pregnant or breastfeeding, 19-50 | 1,000 | 2,500 |
The daily needs are the US RDAs as listed by MedlinePlus, and the pregnancy row is from the National Academies report. The upper limits come from the National Academies, which set them to limit kidney stone risk in adults. The limit counts food and supplements together.
One trap: the Nutrition Facts label uses a Daily Value of 1,300 mg. So a plant milk that says "25% DV" has about 325 mg, which is a third of a 1,000 mg day, not a quarter.
Best non-dairy calcium sources
All values below are from USDA FoodData Central.
| Food | Serving | Calcium (mg) | Calories (kcal) |
|---|---|---|---|
| Firm tofu, calcium sulfate | 1/2 cup (126 g) | 861 | 181 |
| Regular tofu, calcium sulfate | 1/2 cup (124 g) | 434 | 94 |
| Almond milk, unsweetened, fortified | 1 cup (240 ml) | 482 | 39 |
| Sardines in oil, with bones | 3.75 oz can (92 g) | 351 | 191 |
| Soy milk, unsweetened, fortified | 1 cup (240 ml) | 301 | 80 |
| Collard greens, cooked | 1 cup (190 g) | 268 | 63 |
| Turnip greens, cooked | 1 cup (144 g) | 197 | 29 |
| White beans, canned | 1 cup (262 g) | 191 | 299 |
| Pink salmon, canned, with bones | 3 oz (85 g) | 181 | 118 |
| Chia seeds | 1 oz (28 g) | 179 | 138 |
| Kale, cooked | 1 cup (118 g) | 177 | 43 |
| Bok choy, cooked | 1 cup (170 g) | 158 | 20 |
| Edamame | 1 cup (155 g) | 98 | 188 |
| Sesame seeds | 1 tbsp (9 g) | 88 | 52 |
| Almonds | 1 oz (28 g) | 76 | 164 |
| Dried figs | 5 figs (42 g) | 68 | 105 |
| Tahini | 1 tbsp (15 g) | 64 | 89 |
| Broccoli, cooked | 1 cup (156 g) | 62 | 55 |
| For comparison: 2% milk | 1 cup (244 g) | 293 | 122 |
Calories matter if you're tracking. Bok choy and turnip greens deliver calcium for almost nothing, while almonds, tahini and chia bring a lot of energy with modest calcium. White beans are a decent source but cost about 300 calories a cup.
Is plant calcium absorbed as well as milk?
It depends on the plant. Researchers at Creighton and Purdue labeled the calcium in foods with isotopes and measured how much people absorbed.
| Food | Calcium absorbed (%) | Calcium in serving (mg) | Absorbed (mg) |
|---|---|---|---|
| 2% milk, 1 cup | 32 | 293 | 94 |
| Kale, cooked, 1 cup | 41 | 177 | 73 |
| Spinach, cooked, 1 cup | 5 | 245 | 12 |
Absorption figures: kale vs milk in 11 women (41% vs 32%), spinach vs milk in 13 adults (5% vs 28%). The absorbed column multiplies the USDA calcium by those rates.
Spinach is the outlier because it carries enough oxalic acid to bind nearly all of its calcium. MedlinePlus warns that the oxalic acid in spinach and rhubarb binds calcium and keeps it from being absorbed, whatever the label says. Our spinach vs kale comparison covers the rest of their nutrients.
The same research group concluded that most vegetables are absorbed as well as or better than milk, unless they're high in oxalic acid (spinach) or phytic acid (wheat bran). The problem with greens is volume: you'd need several cups a day to cover your needs from vegetables alone, which is why fortified foods and tofu do the heavy lifting.
Calcium-set tofu: how to read the label
Tofu is made by curdling soy milk with a coagulant. When that coagulant is calcium sulfate or calcium chloride, the tofu becomes one of the densest calcium foods there is. When it's magnesium chloride (nigari) alone, calcium can be much lower, so the label matters.
- Look for "calcium sulfate" or "calcium chloride" in the ingredients.
- Check the %DV for calcium on the label and multiply by 13 to get milligrams.
- Firmer tofu packs more calcium per bite because it holds less water: 861 mg per half cup for firm versus 434 mg for regular in USDA data.
For the protein side, see tofu vs chicken.
Fortified plant milks
Fortified soy milk is the closest dairy swap. It has about 301 mg of calcium per cup, close to 2% milk's 293 mg, plus 7 g of protein. Fortified almond milk can carry even more calcium, 482 mg in the USDA entry, but only 1 g of protein.
Calcium in plant milks is added, so it varies a lot by brand, and unfortified or organic versions may have little. A few habits help:
- Choose a carton that lists calcium on the label, ideally 20% DV (260 mg) or more per cup.
- Shake the carton. Added calcium can settle at the bottom.
- Pick unsweetened if you're watching calories.
Our comparisons of cow's milk vs soy milk and oat milk vs almond milk go deeper on protein and calories.
Canned fish with bones
If you eat fish, canned sardines and salmon are an easy win. The calcium is in the soft, edible bones, so buy bone-in and mash them in. A 3.75 oz can of sardines has 351 mg and 23 g of protein. Boneless fillets don't count.
What lowers calcium absorption
- Oxalate: spinach and rhubarb bind most of their own calcium. Enjoy them, but don't count them toward your total.
- Phytate and wheat bran: wheat bran binds calcium eaten at the same meal, per MedlinePlus.
- Salt, protein and caffeine: a review in the American Journal of Clinical Nutrition notes these reduce calcium retention, and they can run high in some plant-based diets. Raising calcium intake is usually easier than cutting all three.
- Cooking method: MedlinePlus advises cooking greens briefly in a little water, steamed or sauteed, to keep more of their calcium.
Vitamin D helps you use calcium
Your body needs vitamin D to use the calcium you eat, which is why cow's milk is fortified with it. Many fortified plant milks also add vitamin D, so check the label. The label Daily Value for vitamin D is 20 mcg. If you choose a calcium supplement, MedlinePlus suggests one that includes vitamin D.
A dairy-free day that hits 1,000 mg
| Meal | Food | Calcium (mg) | Calories (kcal) |
|---|---|---|---|
| Breakfast | 1 cup fortified soy milk in oats or coffee | 301 | 80 |
| Lunch | 1/2 cup regular calcium-set tofu, stir-fried | 434 | 94 |
| Lunch | 1 cup cooked bok choy | 158 | 20 |
| Snack | 1 oz almonds | 76 | 164 |
| Dinner | 1 cup cooked collard greens | 268 | 63 |
| Total | 1,237 | 421 |
The calories shown are for these foods only, before oil and the rest of each meal. No single meal has to carry the whole day. If you're vegan, pair this with our guides to vegan protein sources and iron for vegetarians.
Do you need a calcium supplement?
Food first. Supplements make sense only when your usual intake falls short, and a day like the one above shows that's avoidable.
If you do take one:
- Take no more than 500 mg at a time, and split larger doses through the day.
- Take calcium carbonate with a meal. Calcium citrate is absorbed with or without food.
- Count supplements toward the upper limit of 2,500 mg (2,000 mg over age 50). Extra calcium over a long time raises kidney stone risk in some people.
Talk to your doctor before starting a supplement, especially if you take other medicines, since some of them affect how calcium is absorbed.
Track your calcium in Nutrify
Calcium is easy to miss when it's spread across tofu, greens and a splash of soy milk. Nutrify logs meals from a photo, a barcode scan or a voice note and shows calcium alongside your calories and macros. It comes with a 7-day free trial, then a paid subscription.
Sources
- MedlinePlus (NLM), Calcium in diet.
- MedlinePlus (NLM), Calcium supplements.
- National Academies, Dietary Reference Intakes for Calcium and Vitamin D (2011), chapter 6: tolerable upper intake levels.
- FDA, Daily Value on the Nutrition and Supplement Facts labels.
- Heaney RP, Weaver CM. Calcium absorption from kale. Am J Clin Nutr, 1990.
- Heaney RP, Weaver CM, Recker RR. Calcium absorbability from spinach. Am J Clin Nutr, 1988.
- Weaver CM. Calcium bioavailability and its relation to osteoporosis. Proc Soc Exp Biol Med, 1992.
- Weaver CM, Proulx WR, Heaney R. Choices for achieving adequate dietary calcium with a vegetarian diet. Am J Clin Nutr, 1999.
- USDA FoodData Central (SR Legacy), FDC IDs: firm tofu 172475, regular tofu 172476, almond milk 174832, soy milk 175215, sardines 175139, collards 170407, turnip greens 170466, white beans 175204, pink salmon 174225, chia 170554, kale 169238, bok choy 170391, edamame 168411, sesame seeds 170150, almonds 170567, dried figs 174665, tahini 170189, broccoli 169967, spinach 168463, 2% milk 171267. Search any ID at fdc.nal.usda.gov.
