Most people rarely think about sugar and iron in the same bite, yet the two are closely connected in everyday eating. Sweet foods like dried fruit, dark chocolate, and fortified cereals often carry surprising amounts of iron, while savory staples such as spinach and lentils are nearly sugar-free. This calculator puts both numbers side by side for any serving size, so you can spot a quick iron win and hidden sugar in the same food.
Choose a food, enter your serving size, and set the reference standards that match your goals: daily iron needs range from 8 mg for adult men to 18 mg for premenopausal women to 27 mg during pregnancy, while common sugar guidance is 25 g (WHO/AHA women) or 36 g (AHA men). The tool then estimates sugar in grams, iron in milligrams, and each as a percentage of your target.
Whether you are tracking macros, managing iron levels, or simply curious about a snack, the results include a step-by-step breakdown and an optional head-to-head comparison of two foods.
🧪 1. Choose Your Food
⚙️ 2. Set Your Reference Standards
Quick Start
Pick a food, enter how much you plan to eat (grams or ounces), then choose the iron and sugar targets that fit your situation. The calculator shows the exact grams of sugar and milligrams of iron in that serving, plus the percentage of your daily targets. Tick the compare box to see two foods side by side at the same serving size.
How the Numbers Are Calculated
The tool uses per-100g nutrition values for each food, then scales them to your serving size:
Sugar in serving = (sugar per 100 g ÷ 100) × serving grams
Iron in serving = (iron per 100 g ÷ 100) × serving grams
Percentages are simply the resulting nutrient amount divided by the target you selected. If you enter ounces, the tool converts to grams first using 1 oz = 28.35 g.
Reference Values for Common Foods
| Food (per 100 g) | Sugar (g) | Iron (mg) |
|---|---|---|
| Beef liver, cooked | 0 | 6.5 |
| Spinach, cooked | 0.4 | 3.6 |
| Lentils, cooked | 1.8 | 3.3 |
| Dark chocolate 70–85% | 24 | 11.9 |
| Raisins | 59.2 | 1.9 |
| Banana | 12.2 | 0.3 |
| Apple | 10.4 | 0.1 |
| Fortified bran flakes | 22 | 16.7 |
Values are approximate averages from USDA FoodData Central; actual numbers vary by brand, ripeness, and cooking method.
Worked Example
Choose raisins (59.2 g sugar and 1.9 mg iron per 100 g), serving size 60 g, targets 25 g sugar and 18 mg iron.
Sugar: 59.2 × 0.60 = 35.5 g → 142% of the 25 g target
Iron: 1.9 × 0.60 = 1.1 mg → 6% of the 18 mg target
That small handful of raisins is mostly sugar — useful to know if you're comparing it to a savory iron source like lentils.
Common Mistakes to Avoid
- Confusing the 18 mg adult female target with the lower 8 mg adult male target — the numbers change the iron percentage dramatically.
- Assuming dried fruit is low in sugar because it feels like a whole fruit; drying concentrates both sugar and nutrients.
- Forgetting that plant iron (non-heme iron) is absorbed less efficiently than the heme iron in meat, so a high spinach number doesn't automatically equal an equal iron boost.
- Reading percentages as added sugar; this tool reports total sugar, which includes naturally occurring sugar in fruit and dairy.
Frequently Asked Questions
Why does dark chocolate show a lot of iron? Cocoa solids are naturally rich in iron, so high-percentage dark chocolate can provide several milligrams per serving — but it also brings sugar and calories, so portion control matters.
Is the sugar in fruit the same as added sugar? No. The sugar here is total sugar, including natural fructose and glucose. Health guidance about 25–36 g usually refers to added sugars, so fruit-based sugar should be interpreted with that context.
Can I use this to plan iron-rich meals? Yes. Pair it with foods that help non-heme iron absorption, like vitamin C sources, and avoid tea or coffee right around iron-heavy meals if you are concerned about absorption.
For authoritative background, see the NIH Iron Fact Sheet and the AHA Added Sugars guidance.