Polenta is a comforting, gluten-free staple made from ground corn, but its iron content depends heavily on how it was milled and whether it has been enriched. This Polenta Iron Calculator helps you estimate the milligrams of iron in any serving — whether you measure cooked polenta by the cup, dry polenta by the gram, or simply by the ounce.
Iron supports oxygen transport, energy levels, and immune function, and the amount you need varies by age, sex, and life stage. The calculator lets you set your own daily target, so athletes tracking micronutrients, dietitians planning menus, or anyone managing low iron can get a more useful answer than a generic percentage.
Select your polenta type, enter your serving size, and adjust the daily value if you like. The breakdown shows your result step by step, so you can see exactly how the number is calculated.
🍚 Polenta Iron Calculator
Estimate iron (mg), your % daily value, and see the step-by-step math.
Default 18 mg (FDA Daily Value). Adult men ~8 mg, premenopausal women ~18 mg.
How to Use This Tool
Step 1 — Choose the polenta type. The drop-down includes cooked enriched polenta, dry enriched cornmeal/polenta, and dry whole-grain cornmeal. If you are measuring leftovers or a prepared batch, choose cooked polenta. If you are portioning dry polenta from the packet, choose an appropriate dry option.
Step 2 — Enter your serving size. You can type the number and select grams, ounces, or cups. The calculator converts cups using typical packed weights: 1 cup cooked polenta ≈ 250 g and 1 cup dry polenta ≈ 156 g.
Step 3 — Set a personal daily target. The FDA Daily Value for iron is 18 mg, but your needs differ: most adult men need about 8 mg/day, while premenopausal women need about 18 mg/day; pregnancy can raise needs to 27 mg/day. You can adjust this number to match your goals or dietary plan.
Step 4 — Calculate and review. Press Calculate Iron to see the iron milligrams, percent of target, a visual progress bar, and a step-by-step calculation. Use the preset buttons for quick common servings.
The Math Behind It
Iron content is calculated from a simple density-based formula:
Iron (mg) = serving weight (g) × (iron per 100 g ÷ 100)
To use the formula, the calculator first converts your serving into grams:
- ounces × 28.3495 = grams
- cups of cooked polenta × 250 = grams
- cups of dry polenta × 156 = grams
Then the percent of your daily target is:
% daily value = iron (mg) ÷ daily target (mg) × 100
The iron-per-100 g figures used in this calculator are based on typical USDA values for enriched and whole-grain corn products. Enriched dry cornmeal contains about 4.75 mg iron per 100 g, whole-grain dry cornmeal about 3.45 mg per 100 g, and cooked enriched polenta about 1.02 mg per 100 g because cooking adds water and dilutes the nutrient concentration by weight.
Worked Examples
Example 1: Cooked polenta by the cup. You eat 1.5 cups of cooked enriched polenta. The calculator converts 1.5 cups × 250 g/cup = 375 g. Then 375 g × (1.02 ÷ 100) = 3.83 mg of iron. With an 18 mg target, that is 3.83 ÷ 18 × 100 = 21.3% of your daily value.
Example 2: Dry whole-grain polenta by weight. You plan to cook 2 oz (56.7 g) of dry whole-grain cornmeal. Iron = 56.7 × (3.45 ÷ 100) = 1.96 mg. That is 10.9% of the 18 mg target.
Example 3: Adjusting the target. A meal plan designed for a female athlete uses a 25 mg daily iron goal. An 80 g serving of dry enriched polenta provides 80 × (4.75 ÷ 100) = 3.80 mg, which is 15.2% of her adjusted target.
Reference: Iron Content by Polenta Type
| Polenta / cornmeal type | Iron per 100 g | Notes |
|---|---|---|
| Cooked polenta (enriched, prepared with water) | ≈ 1.02 mg | Diluted by water; still contributes to intake |
| Dry enriched cornmeal / dry polenta | ≈ 4.75 mg | Fortified with iron; check package label |
| Dry whole-grain cornmeal | ≈ 3.45 mg | Naturally occurring iron, no enrichment |
Weights: 1 cup cooked polenta ≈ 250 g · 1 cup dry polenta ≈ 156 g · 1 oz = 28.35 g.
Factors Affecting Accuracy
Enrichment is the biggest variable. In the United States, most degermed cornmeal is enriched with iron, but imported or traditional stone-ground polenta may not be. Some specialty Italian polenta is unenriched, so the actual iron value could be closer to 0.5–1.5 mg per 100 g dry. Always check the nutrition label for "enriched" or "iron added".
Moisture and preparation matter. The same dry amount cooked with more water produces a softer polenta with a lower iron concentration per gram. Storing and reheating can also change weight slightly. For the most consistent tracking, weigh the dry polenta before cooking rather than estimating the prepared volume.
Additions change the meal, not the polenta. Cheese, butter, tomatoes, spinach, or red sauce alter the total iron and calories of your plate; the calculator isolates the polenta portion only.
Cup measurements are approximate. A loosely scooped cup of dry cornmeal can weigh 140–170 g depending on how tightly it is packed, which shifts the final iron by roughly 10%.
Frequently Asked Questions
Is polenta a good source of iron? Enriched polenta can make a modest contribution, especially for people eating plant-forward diets, but it is not as concentrated as beans, lentils, fortified oatmeal, or organ meats. For comparison, a typical cooked serving of enriched polenta (about 1 cup) provides roughly 2.5 mg iron, whereas a cup of cooked lentils can provide more than 6 mg.
Why is 100 g of dry polenta higher in iron than 100 g of cooked polenta? All values are per 100 g of that product as eaten. Dry polenta is essentially cooked polenta with the water removed, so the mineral is concentrated. If you cook 100 g of dry polenta with water, the final batch weighs much more but contains the same total iron.
How can I improve iron absorption from polenta? The iron in corn is non-heme iron, which the body absorbs less efficiently than the heme iron in meat. Pairing polenta with vitamin C-rich foods such as roasted peppers, tomato sauce, citrus, or broccoli can improve absorption. Avoid drinking tea or coffee within an hour of an iron-rich meal if absorption is a concern.
Can this calculator help with a low-iron diet plan? Yes — set your daily target to your RDA or the value your dietitian recommends, then compare servings across staple foods. The lentil iron calculator and oatmeal iron calculator are useful for comparing other plant-based staples. For clinical guidance, see the NIH Iron Fact Sheet for Health Professionals.