A single serving of raw spinach is 1 cup, which weighs about 30 grams (roughly 1 ounce). That’s lighter than it sounds. One cup of raw spinach leaves is a loose, fluffy portion, not a tightly packed one. If you don’t have a measuring cup handy, think of it as about two cupped handfuls.
What a Cup of Raw Spinach Actually Looks Like
Spinach leaves are so airy that a full cup doesn’t amount to much weight. Thirty grams is barely enough to register on a kitchen scale, which is why spinach portions can feel deceptively large by volume but small by mass. If you’re building a salad, one serving is roughly the amount that would loosely fill a standard coffee mug. Most people eating a spinach salad as a side dish end up consuming two or three servings without realizing it, which is perfectly fine.
For context, federal dietary guidelines recommend adults eat 2 to 3 cup-equivalents of vegetables daily. A couple of generous handfuls of spinach in a salad or smoothie checks off a meaningful portion of that goal.
Raw vs. Cooked: The Shrink Factor
Spinach loses a dramatic amount of volume when heated. One cup of raw spinach cooks down to about a quarter cup. That means if a recipe calls for 1 cup of cooked spinach, you’ll need roughly 4 cups of raw leaves to get there. This matters when you’re following recipes or tracking nutrition, because the nutrient density per cup changes significantly once water cooks out and the leaves compress.
On nutrition labels and in most dietary databases, raw spinach and cooked spinach are listed separately for exactly this reason. If you’re logging food intake, make sure you’re selecting the right form.
Nutrients in a Single Serving
A 1-cup serving of raw spinach delivers 16 mcg of vitamin A and 5 mg of iron. It’s also one of the richest food sources of vitamin K, the nutrient that helps your blood clot normally. The American Heart Association classifies spinach as a high-vitamin-K food, meaning a single serving contains more than 60 mcg.
Because spinach is so low in calories (about 7 per cup), you get a strong nutrient return for very little energy cost. Doubling or tripling your portion in a salad multiplies those vitamins proportionally without adding significant calories.
Spinach and Blood Thinners
If you take warfarin or a similar anticoagulant, the vitamin K content in spinach is worth paying attention to. Vitamin K directly influences how the medication works, and eating inconsistent amounts can cause your blood-clotting levels to fluctuate. The key isn’t avoiding spinach altogether. It’s keeping your intake steady from day to day and week to week, so your medication dose stays properly calibrated. Large, unpredictable swings in spinach consumption are what create problems.
Oxalates: What to Know About Kidney Stones
Raw spinach contains a compound called oxalate, which can contribute to calcium-oxalate kidney stones in people who are susceptible. A single cup of raw spinach has about 656 mg of oxalates, which is classified as very high compared to most other vegetables. For most people, this isn’t an issue. Your body handles normal dietary oxalate without trouble. But if you’ve had kidney stones before or have been told you’re at elevated risk, eating large quantities of raw spinach regularly is worth discussing with whoever manages your care.
Cooking spinach and discarding the water reduces oxalate content meaningfully. So if you love spinach but want to lower your oxalate exposure, sautéing or blanching is a practical option.
How to Measure Without a Measuring Cup
The easiest visual shortcut: cup both hands together loosely and grab a portion of spinach leaves. That double handful is approximately one cup, or one serving. If you’re tossing spinach into a smoothie, a large pinch-grab from the bag, enough to lightly fill both palms, gets you close. Precision matters less here than with denser foods. Being off by a few leaves won’t change your nutritional intake in any meaningful way.
For salads, most people serve themselves 2 to 3 cups as a base, which counts as 2 to 3 vegetable servings. That’s a solid contribution toward daily intake goals and nothing to worry about for the average person.