How the numbers are built
First the tool estimates TDEE with Mifflin–St Jeor and the same activity factors as the calorie calculator. Then it applies a 25 / 45 / 30 energy split: a quarter of calories from protein, 45 percent from carbohydrate, 30 percent from fat. Grams follow the usual Atwater factors — 4 kcal per gram of protein or carbohydrate, 9 kcal per gram of fat.
A 2,000 kcal day in that split is about 125 g protein, 225 g carbohydrate, and 67 g fat. Those grams are a sketch for shopping, not a law. People with kidney disease, diabetes on insulin, or a clinician-set carbohydrate target should ignore this page and follow the plan they already have.
Worked example
A 42-year-old woman, 168 cm, 72 kg, moderate activity, lands near 2,170 kcal on the calorie tool. Twenty-five percent is 543 kcal of protein, about 136 g. That is close to 1.9 g per kilogram — higher than the everyday floor on the protein calculator. If that feels like too much food, drop toward 1.2–1.6 g per kg and let carbohydrate take the rest.
Putting macros on a plate
Macros only help if dinner exists. Use the meal framework, the weeknight dinners, and the protein-at-meals note. Do not chase fat grams while skipping vegetables. Do not open a crash cut the same week; read why crash diets fail first.
Frequently asked
Does the macro calculator store what I type?
No. The arithmetic runs in your browser. See the privacy page.
Is this medical advice?
No. Read the medical disclaimer. Take unusual results to a clinician.
Should children use this?
No. These tools are written for adults.
How does this sit next to BMI?
Use the BMI calculator as a size snapshot, then return here for the question this page actually answers.
What should I read after the number?
Food: meal framework. Joints: knees or back. Metrics: adult indicators.
Formulas are named on the page. They are planning maths, not clinic devices.
Using the result in a normal week
Write the figure once. Do not recalculate after every meal. Recalculate when weight has changed by several kilograms, when a clinician has changed a medicine that affects weight or heart rate, or when your job has become much more or much less physical. Daily recalculation is how a useful tool becomes noise.
Food still comes from the meal framework, the foods list, and the dinner templates in the journal. Movement still comes from walking and from the mobility articles when a joint is the limit. Metrics still come from waist, blood pressure, and sleep on the adult-indicator pages.
If the result looks extreme, assume the inputs or the equation limits before you assume your body is extreme. Heights typed in the wrong unit are the usual villains. Then talk to a person who can examine you.
Keep the same units you used last time. Measure height once against a wall and write it in the notebook you already keep for waist, morning weight, and walks. Consistency beats precision theatre.
Using the result in a normal week
Write the figure once. Do not recalculate after every meal. Recalculate when weight has changed by several kilograms, when a clinician has changed a medicine that affects weight or heart rate, or when your job has become much more or much less physical. Daily recalculation is how a useful tool becomes noise.
Food still comes from the meal framework, the foods list, and the dinner templates. Movement still comes from walking and from the mobility articles when a joint is the limit. Metrics still come from waist, blood pressure, and sleep — see adult indicators and home blood pressure.
Shortcuts that promise to replace this work are collected in why crash diets fail and teas, wraps, and shortcuts. Read those if the reason you opened a calculator was a product promise rather than a planning question.
If the result looks extreme, assume the inputs or the equation limits before you assume your body is extreme. Heights under 140 cm or weights typed in the wrong unit are the usual villains. Then talk to a person who can examine you. A second calculator tab is not that person.
Keep the same units you used last time. Mixing pounds and kilograms, or inches and centimetres, is the most common way to get a theatrical result. When in doubt, measure height once against a wall and write it in the notebook you already keep for waist, morning weight, and walks. Consistency beats precision theatre.