How we calculate

We want every number on this site to be checkable. Here is where the targets, food data and tips come from — and what the calculator doesn’t account for.

Daily calorie needs

Resting energy expenditure is calculated with the Mifflin–St Jeor equation (Mifflin et al., 1990). It was derived from measurements in 498 healthy people aged 19–78; in the same study the older Harris–Benedict equations overestimated needs by 5% on average.

Men:   10 × weight (kg) + 6.25 × height (cm) − 5 × age (y) + 5
Women: 10 × weight (kg) + 6.25 × height (cm) − 5 × age (y) − 161

We then multiply by an activity factor — from 1.2 (sedentary) to 1.9 (physical work or training twice a day) — and adjust for your goal: −15% to lose weight, +10% to gain.

Protein, fat and carbs

Calories are split between protein, fat and carbs using a typical split for your goal (25/30/45% to maintain weight) or your own. One gram of protein or carbs provides 4 kcal, fat 9 kcal.

• saturated fat — no more than 10% of calories (WHO);
• omega-6 — about 4% of calories, omega-3 — 0.5% (EFSA);
• fiber — 14 g per 1,000 kcal;
• sugar — no more than 10% of calories.

Vitamins and minerals

Targets are Recommended Dietary Allowances (RDA) or Adequate Intakes (AI) for adults from the NIH Office of Dietary Supplements and the US National Academies; they depend on sex and age. Pregnancy, breastfeeding, childhood and medical conditions aren’t covered — targets differ there.

Food and dish data

Food composition comes from USDA FoodData Central (Foundation Foods and SR Legacy). Each food is pinned to a specific database record, described and linked on its food page. Ukrainian dishes are calculated from recipes: the raw weight of each ingredient with cooking taken into account, divided by the weight of the finished dish.

How cooking is handled

Grains absorb water when boiled and meat loses it when fried, so 100 g cooked has different calories from 100 g raw. For grains and legumes the yield comes from raw–boiled pairs in the USDA database (buckwheat ×3.76, pasta ×2.35); for other foods it is an average for the category.

Some vitamins break down with heat or leach into the water. For grains and legumes we take these losses from the same USDA raw–boiled pairs, separately for each vitamin and mineral: cooked buckwheat keeps about 68% of its vitamin B1 and 87% of its magnesium. The raw and cooked samples differ, so sometimes the cooked one shows more of a nutrient than the raw had; we then treat it as fully retained. For other foods and cooking methods the losses are approximate percentages for nutrient groups (vitamin C, B vitamins, fat-soluble vitamins, minerals), not lab data for each food.

Food-pairing tips

Every tip — tea and iron, vitamin C, calcium, fat and carotenoids — rests on studies we checked against the original on PubMed; the link is under each tip. How much iron or calcium you actually absorb depends heavily on the whole meal, so we don’t compute “absorbed milligrams”; we show what helps and what hinders. More in the articles.

Limitations

• The formulas estimate needs for an average person; your actual energy use can differ noticeably. The best guide is how your weight changes over a few weeks.
• The calculator doesn’t replace advice from a doctor or dietitian, especially with medical conditions, in pregnancy and for children.
• Your profile, diary and custom foods are stored only in your browser — we don’t see or share them.