Precision Nutrition Macro Calculator 2026: Calculate Your Daily Caloric Intake

Key takeaways

Energy: Mifflin-St Jeor BMR (or Katch-McArdle if you know your body-fat %) × activity factor = TDEE.¹
Protein: 1.2–1.6 g/kg per day for most adults (DGA 2025–2030), up to 2.0 g/kg for resistance training.³⁴
Fat and fibre: at least 20% of calories from fat, saturated fat under 10%, fibre 14 g per 1,000 kcal.³⁶

Macro calculator: your personalised daily targets

How your macros are calculated

This macronutrient calculator follows four evidence-based steps. Every number is an estimate with roughly ±10% individual error, so track your weight and energy for 2–3 weeks and adjust.

Step	Method
1. BMR	Mifflin-St Jeor: 10×kg + 6.25×cm − 5×age + 5 (men) or −161 (women). It had the best accuracy in a systematic review of resting metabolic rate equations.¹² If you enter body fat, Katch-McArdle is used: 370 + 21.6 × lean mass (kg).
2. TDEE	BMR × physical activity factor (1.2–1.9), then −20% (fat loss) or +10% (muscle gain). Floors of 1,200 kcal (women) and 1,500 kcal (men) apply.
3. Protein	1.4–2.0 g/kg depending on goal and style, capped at 35% of energy.³⁴⁵ Splitting intake over about four meals supports muscle protein synthesis.⁷
4. Fat and carbs	Fat is 25–40% of calories (never below the 20% AMDR floor); carbohydrate fills the remainder. Fibre is 14 g/1,000 kcal and saturated fat is kept under 10% of energy.³⁶

Protein is based on total body weight. People with obesity, kidney disease or other conditions should have protein targets set by a dietitian.

Macros and total parenteral nutrition (TPN)

Total parenteral nutrition (TPN) uses the same macronutrient arithmetic as this calculator, delivered intravenously: dextrose provides about 3.4 kcal/g, amino acids 4 kcal/g and lipid emulsion about 10 kcal/g.¹⁰ The difference is precision and risk. In critically ill adults, ESPEN advises about 20–25 kcal/kg/day, progressive protein of about 1.3 g/kg/day, glucose no higher than 5 mg/kg/min and lipids no higher than 1.5 g/kg/day.⁸ Long-term home parenteral nutrition for intestinal failure is likewise individually prescribed and monitored.⁹ Use this tool to understand the principles, never to prescribe or adjust TPN.

Frequently asked questions

How do I calculate my macros?

Estimate resting energy with Mifflin-St Jeor (or Katch-McArdle if body fat is known), multiply by an activity factor to get TDEE, adjust for your goal, set protein per kg of body weight and fat as a share of calories, then fill the remainder with carbohydrate.

How much protein do I need per day?

The adult RDA is 0.8 g/kg. The Dietary Guidelines for Americans 2025–2030 advise 1.2–1.6 g/kg, and the ISSN suggests 1.4–2.0 g/kg for people who exercise.³⁴

What is the difference between BMR and TDEE?

BMR is the energy your body uses at rest. TDEE is BMR multiplied by an activity factor and represents the calories needed to maintain body weight.

Can this macro calculator be used for tube feeding or total parenteral nutrition?

No. Total parenteral nutrition and enteral feeding are prescribed individually by a clinical nutrition team using patient-specific monitoring. This tool is for healthy adults eating by mouth.

References

Mifflin MD, et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990;51(2):241–247. doi:10.1093/ajcn/51.2.241
Frankenfield D, et al. Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. J Am Diet Assoc. 2005;105(5):775–789. doi:10.1016/j.jada.2005.02.005
U.S. Department of Health and Human Services and USDA. Dietary Guidelines for Americans, 2025–2030. Released 7 January 2026. dietaryguidelines.gov
Jäger R, et al. International Society of Sports Nutrition position stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20. doi:10.1186/s12970-017-0177-8
Aragon AA, et al. International Society of Sports Nutrition position stand: diets and body composition. J Int Soc Sports Nutr. 2017;14:16. doi:10.1186/s12970-017-0174-y
Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. National Academies Press; 2005. doi:10.17226/10490
Schoenfeld BJ, Aragon AA. How much protein can the body use in a single meal for muscle-building? J Int Soc Sports Nutr. 2018;15:10. doi:10.1186/s12970-018-0215-1
Singer P, et al. ESPEN guideline on clinical nutrition in the intensive care unit. Clin Nutr. 2019;38(1):48–79. doi:10.1016/j.clnu.2018.08.037
Pironi L, et al. ESPEN guideline on chronic intestinal failure in adults – update 2023. Clin Nutr. 2023;42(10):1940–2021. doi:10.1016/j.clnu.2023.07.019
Ayers P, et al. A.S.P.E.N. parenteral nutrition safe practices for adults. JPEN. 2014;38(3):296–333. doi:10.1177/0148607114526450

Medical disclaimer

Educational use only. This calculator provides general estimates for healthy adults and is not medical advice, diagnosis or treatment. It does not create a clinician–patient relationship. Do not use it if you are under 18, pregnant or breastfeeding, have diabetes, kidney or liver disease, a history of disordered eating, or receive enteral or parenteral nutrition. Speak to a physician or registered dietitian before changing your diet, especially if you take medication or have a medical condition. Stop and seek care if you feel unwell.