1. Estimate expenditure
Mifflin–St Jeor predicts basal metabolic rate from body mass, stature, age, and the equation’s sex constant. Your activity selection scales that figure into TDEE.
Free nutrition planning tool
Macro Intake Calculator
Shape a practical daily fuel mix for fat loss, weight stability, or lean gain. Enter kg and cm or switch to lb and inches; your measurements convert automatically.
A starting estimate, not a fixed prescription. Calibrate the energy target against your average body-weight trend, gym performance, hunger, and recovery.
Method & application
How the recommendation is assembled
The model creates an energy budget first, reserves protein and fat, then assigns the balance to carbohydrate.
2. Match the phase
The selected objective sets calories at 85%, 100%, or 107.5% of estimated daily expenditure. Your observed weight trend shows whether that starting adjustment fits.
3. Divide the budget
Protein uses 1.6 g/kg, dietary fat receives one quarter of calories, and carbs take the unassigned portion to support activity and lifting.
Reading your macro result
Precision on screen does not imply perfect knowledge of your metabolism. Use the output as a structured opening bid.
Judge the trend
Weigh under similar conditions and compare weekly averages. After two to four consistent weeks, a flat, rising, or falling trend reveals whether the calorie budget fits your goal.
Adjust in small steps, then observe againAllow flexible meals
Daily numbers can vary while the weekly average remains aligned. Keep protein reasonably steady and let carbohydrate and fat flex around preference, appetite, and training demands.
Consistency beats gram-perfect trackingLimits and safety
Prediction equations can miss individual expenditure because spontaneous movement, occupation, training volume, body composition, and adaptation vary. The activity multiplier is the largest source of uncertainty, so real-world feedback matters more than the initial estimate.
This adult fitness tool is not medical nutrition advice. Do not use it as a substitute for individualized care during pregnancy or breastfeeding, under age 18, with a history of disordered eating, or when a condition or medication affects nutrition. A registered dietitian or qualified clinician can provide suitable guidance.
To avoid presenting very-low-calorie diets as routine targets, the calculator stops below 1,500 kcal for the male equation and 1,200 kcal for the female equation. That safeguard is a scope limit, not a claim that every intake above it is appropriate.
The sex field reflects the constants used in the published equation; it is not intended to define identity. If neither option represents your physiology well, compare both outputs and seek professional interpretation when accuracy is important.
Formula and nutrition references
The resting estimate follows the original Mifflin–St Jeor research paper. The protein anchor is informed by a systematic review and meta-analysis of resistance training, which found that gains in fat-free mass plateaued around 1.6 g/kg/day on average. Fat and carbohydrate are energy-allocation choices rather than clinical prescriptions; broader acceptable ranges are described in the National Academies dietary reference intake report.
Next steps for your nutrition plan
Cross-check the calorie baseline, explore the dedicated protein tool, or connect nutrition with your training data.
Macro calculator questions
Details on the assumptions, everyday use, and when generic estimates are not enough.
How does this macro calculator set calories?
It estimates resting energy with the Mifflin–St Jeor equation, applies an activity multiplier, and then uses 85% of TDEE for fat loss, 100% for maintenance, or 107.5% for lean gain.
How are protein, fat, and carbohydrates divided?
Protein is set at 1.6 grams per kilogram of body weight, fat receives 25% of target calories, and carbohydrate fills the remaining energy.
Should I eat the exact numbers every day?
Treat the figures as starting points rather than exact prescriptions. A consistent weekly average is generally more useful than matching every gram each day.
When should I adjust my macro targets?
Hold intake steady long enough to observe a two-to-four-week body-weight trend. If progress differs from the intended direction, change calories modestly and reassess.
Can this calculator replace advice from a dietitian?
No. It is a general planning aid for adults and cannot account for medical conditions, pregnancy, disordered eating, medications, or individualized clinical needs.