Calorie & Macro Calculator

How this calorie and macro calculator works

Your calorie target is an estimate of daily energy intake. Your macros divide that energy into protein, carbohydrates, and fat. This tool first estimates resting energy, accounts for activity, and applies your selected goal and macro preference.

The equations estimate population averages. They cannot measure your metabolism or promise a particular rate of weight change. This calculator is for adults aged 18–100; the original Mifflin–St Jeor study included adults aged 19–78, so estimates beyond that study range carry additional uncertainty.

1. Estimate resting energy with Mifflin–St Jeor

The published equations use weight in kilograms, height in centimeters, and age in years:

• Male equation: 10 × weight + 6.25 × height − 5 × age + 5
• Female equation: 10 × weight + 6.25 × height − 5 × age − 161

The result estimates resting energy expenditure, often called BMR in online calculators. Resting metabolic rate and basal metabolic rate use different measurement conditions; neither is a recommended daily intake. The formula comes from Mifflin and colleagues’ original study.

The Gender field selects the corresponding published coefficient. “Prefer not to say” calculates both equations and displays their calorie and macro estimates as a range, without averaging them. This is the span between two formula outputs, not a confidence interval or a measured range of your needs. If either estimate falls outside the self-service limits below, the tool withholds the range. Neither coefficient captures individual body composition or the effects of hormone therapy. If neither is a suitable fit, a clinician can help interpret the estimate or arrange a measurement.

2. Estimate total daily energy expenditure (TDEE)

We multiply the resting estimate by an activity factor:

These are common calculator conventions, not measured activity levels or coefficients from the original Mifflin study. Consider work, walking, household activity, and training together. Exercise frequency alone cannot establish your total energy use. Different calculators can use different activity models; for example, the NIDDK Body Weight Planner models changes over time.

3. Choose a starting calorie adjustment

This tool uses the following product defaults, not universal clinical prescriptions:

• Maintain: estimated TDEE.
• Lose: 15% below estimated TDEE, with a maximum reduction of 500 kcal/day.
• Gain: 10% above estimated TDEE, with a maximum addition of 300 kcal/day.

A distant goal weight does not automatically justify a larger deficit. We do not predict a date or weekly rate of weight change from a fixed calorie-to-weight conversion. Metabolism, activity, and body weight can change over time.

The tool withholds calorie and macro targets below 1,200 kcal for the female equation or 1,500 kcal for the male equation, and withholds loss targets at a BMI below 18.5. These are conservative self-service boundaries, not proof that an intake above them is appropriate. They are informed by the intake ranges discussed in the NHLBI adult obesity evidence review; that clinical context does not make this tool a treatment plan.

4. Turn calories into macro grams

Choose a starting preference:

Protein and carbohydrates provide approximately 4 kcal per gram; fat provides 9. We multiply total calories by each percentage, then divide by its energy per gram. Gram values are rounded, so their energy total can differ slightly from displayed calories.

These splits are planning presets. The National Academies’ adult macronutrient ranges are broader: 10–35% protein, 45–65% carbohydrate, and 20–35% fat. The higher-protein preset’s 40% carbohydrate share is below that general carbohydrate range; it is not a recommendation for everyone.

A percentage-based protein allocation is different from a weight-based protein estimate. Use the protein calculator to explore a range for your weight and training goal, then adjust your plan with appropriate guidance. This tool does not impose a grams-per-kilogram floor that can consume the whole calorie budget.

A worked example

For a 30-year-old using the male equation, weighing 80 kg at 180 cm, with moderate activity:

1. Resting energy: 1,780 kcal/day.
2. TDEE: 1,780 × 1.55 = 2,759 kcal/day.
3. Maintain goal: 2,759 kcal/day.
4. Balanced split: approximately 172 g protein, 310 g carbs, and 92 g fat.

The same profile selecting loss gets an initial adjustment of about 414 kcal, giving 2,345 kcal/day. These are example calculations, not a recommended intake for the reader.

What about sugar, fiber, sodium, and cholesterol?

This calculator focuses on energy and macros. Public-health reference values are not all personalized nutrient prescriptions. For example, the FDA’s Daily Values are used for food labeling.

The WHO sugar guideline recommends free sugars below 10% of total energy, with a conditional recommendation below 5% for additional benefit. At 2,000 kcal, those levels correspond to 50 g and 25 g respectively. 25 g is not 5% of every calorie target. Free sugars and total sugars are also different measures.

Use individualized advice for medical nutrient limits. Our macro-tracking guide explains how daily targets relate to food entries.

Calorie and macro calculator questions

How accurate is a calorie calculator?

It is a starting estimate. A systematic review of resting metabolic rate equations found Mifflin–St Jeor useful compared with other commonly used equations, but individual errors remain. Adding an activity estimate adds uncertainty. We do not claim your TDEE is accurate within a fixed 200 kcal.

What is the difference between BMR and TDEE?

BMR describes energy at basal rest. TDEE includes activity and other daily energy costs. Our resting-energy equation approximates the first; an activity multiplier estimates the second. Your resting estimate is not a calorie floor or a complete food target.

Can I calculate calories for weight loss?

Yes. Select “Lose weight” for the tool’s modest starting adjustment. It is not a promise of weight loss or a substitute for clinical care. Review appetite, energy, and trends over 2–4 weeks rather than treating day-to-day scale changes as proof of fat change. People who should not pursue self-directed restriction should use individualized guidance.

Why do the two protein estimates differ?

The macro tool divides your calorie budget using a selected percentage. The protein tool uses grams per kilogram for a selected goal. They answer related but different questions; neither can determine a unique optimum for every person.

Do I need an account? Are my measurements saved?

No account is needed. Calculation inputs remain in this page’s browser state, are not sent with our analytics, and are cleared when the page is reloaded. “Copy your plan” copies the displayed summary only when you request it.

Who should use a different approach?

These tools are not designed for children, pregnancy, breastfeeding, or eating-disorder recovery. Medical conditions, unusually high training demands, and prescribed diets need individualized care. For a time-based model, explore the NIDDK Body Weight Planner.

Use the estimate in context

A daily target does not reveal what is in a meal. Read how Mindful estimates calories and macros to understand portion assumptions and corrections, or browse all free nutrition tools.