Macros Calculator (Percentage Split)
Plan your daily calories as a protein/carb/fat percentage split, computed from your body stats, activity and goal.
Macros Calculator Tool
Gender
Body Stats
Activity Level
Goal
Diet Style
Total: 0% (must equal 100%)
Disclaimer: Macro estimates are general guides only and are not a substitute for personalised dietary advice. Consult a qualified dietitian before making significant changes to your diet, especially if you have a medical condition (diabetes, kidney disease, etc.).
How to Use the Macros Calculator
Enter your body stats and activity level
Toggle between Metric (kg/cm) or Imperial (lb/ft), then enter your age (18 or over — the equation is for adults), gender, height, and weight. Select your activity level from the dropdown. The five multipliers (1.2 to 1.9) are a calculator convention rather than part of the Mifflin-St Jeor paper; FAO/WHO/UNU put a sedentary or light lifestyle at 1.40–1.69 times basal metabolism, so the bottom rung here sits below even that.
Choose your goal and diet style
Pick Lose Fat (500 kcal a day under your estimated expenditure), Build Muscle (300 kcal over) or Maintain Weight. Then select a diet style: Balanced, High Protein, Low Carb, Keto, or Custom. Both are rules of thumb, not prescriptions.
Calculate your daily macros
Click Calculate My Macros. Results show your daily calorie target, then protein, carbs and fat in grams, kilocalories and percentage. Underneath, the page converts your protein into grams per kg of body weight, says when a split sits outside the adult reference ranges, and flags a weight-loss target under 1,200 kcal a day, the line NICE draws for specialist supervision.
Use Custom for your own macro split
Select Custom in the Diet Style dropdown to enter your own protein/carbs/fat percentages. They must sum to exactly 100%. This is ideal if your dietitian or coach has given you a specific macro prescription.
Macronutrients — Beyond Calorie Counting
This calculator works in percentages of your calorie target: it estimates your energy budget with Mifflin-St Jeor, then splits it into protein, carbs and fat at 4, 4 and 9 kcal per gram. A percentage of calories is not the same as a dose of protein, so under every result the page converts the protein share back into grams per kg of body weight and sets it against the RDA of 0.8 g/kg — a floor, not an optimum — and the ISSN's 1.4–2.0 g/kg for people who exercise. It also says when a split falls outside the Acceptable Macronutrient Distribution Ranges for adults: protein 10–35%, carbohydrate 45–65% and fat 20–35% of energy. Prefer to anchor protein to your body weight directly, sports-nutrition style? Our body-weight macro calculator does exactly that: you set protein in grams per kg (2.0 g/kg by default), fat as a share of calories, and carbs fill the rest. Our TDEE calculator also splits its macros by body weight, at a fixed 1.6 g per kg when your goal is losing or gaining weight and 0.8 g per kg when it is maintaining.
What Are Macros and Why the Split Matters, Not Only the Total
Macronutrients — protein, carbohydrates, and fat — are the three categories of nutrients your body uses for energy and structural repair. Unlike micronutrients (vitamins and minerals), macros are consumed in large quantities every day and provide the raw fuel for every physical and cognitive function you perform.
Protein is responsible for building and repairing muscle tissue, producing enzymes and hormones, and supporting immune function. Carbohydrates are your body's primary and preferred energy source — particularly for the brain and during high-intensity exercise. Fat is essential for hormone production, absorption of fat-soluble vitamins (A, D, E, K), and maintaining cellular membrane integrity.
Here is why the split matters, not only the total: each macronutrient has a different thermic effect — the energy cost of digesting it. Westerterp's 2004 review gives reported diet-induced thermogenesis of 20–30% for protein, 5–10% for carbohydrate and 0–3% for fat, and about 10% of the energy eaten for a mixed diet — so roughly a quarter of the calories in protein are "spent" on processing it. At the same 2,000 kcal, a diet that is 40% protein therefore leaves fewer usable calories than one that is 40% fat; how much that changes body composition depends on your training and the rest of your diet.
A percentage of calories is a share of a number. Grams per kilogram is a share of you. Read both.
Protein for Asian Bodies
The US Recommended Dietary Allowance for protein is 0.8 g per kilogram of body weight a day, and the WHO/FAO/UNU safe level is 0.83 g/kg — the intake that meets the needs of 97.5% of healthy adults. Both are floors for maintaining tissue, not targets for changing body composition. For people who exercise, the International Society of Sports Nutrition (ISSN) 2017 position stand puts 1.4–2.0 g/kg a day as sufficient for most, and says 2.3–3.1 g/kg may be needed to keep lean mass in resistance-trained people during a calorie deficit.
For Asian populations specifically, a 2004 WHO expert consultation reviewed evidence that Asian populations have different associations between BMI, percentage of body fat and health risk than European populations, and concluded that the share of Asian people at high risk of type 2 diabetes and cardiovascular disease is substantial at BMIs below the standard overweight cut-off of 25. A body-weight number alone says little about how much of that weight is muscle, which is one more reason to look at protein per kilogram rather than only at a percentage.
Singapore and Malaysia are well supplied with affordable protein: tofu, tempeh (the fermented soybean cake common in Malay and Indonesian cooking), fish, eggs and chicken. The hawker challenge is less about ingredients than proportions: in many rice and noodle dishes the protein arrives as a modest portion beside a large serving of starch, so the plate tilts towards carbohydrate. Check a food-composition table or the label for exact figures; protein per 100 g varies a great deal with how the food is prepared.
Carb Cycling, Keto and High-Protein in Singapore's Food Culture
Ketogenic diets usually cut carbohydrate to less than 50 g a day (Paoli et al., 2013). That is 200 kcal — 10% of a 2,000 kcal day, not the 5% often quoted; the Keto preset here, at 5%, is stricter, about 25 g at 2,000 kcal. It is genuinely hard to sustain in Singapore, where rice, noodles and bread are not side dishes but the foundation of most hawker meals.
People who do follow it locally tend to lean on substitutes such as cauliflower rice and shirataki noodles, and on ordering "less rice" or "no noodles" at the stall. Both the Low Carb and Keto presets sit outside the adult reference ranges for carbohydrate and fat, and the page says so when you pick them — a deliberate choice, but no longer a mainstream split.
A common middle ground is to set protein first (the ISSN's 1.4–2.0 g/kg for people who exercise), give carbohydrate what training needs, and let fat fill the rest of the budget. That is a grams-per-kilogram method, which this page does not use; our body-weight macro calculator does.
For endurance athletes — marathoners at the Sundown Marathon or the Standard Chartered Singapore Marathon, say — carbohydrate is a performance variable, not just a weight-management one. Burke and colleagues (2011) put 30–60 g an hour as an appropriate target during longer events and up to 90 g an hour for events over 2.5 hours, which is hard to square with a 5% carbohydrate day. Carb cycling — more carbohydrate around training, less on rest days — is one compromise; work it out with a sports dietitian.
Fat carries nine calories a gram; protein burns a quarter of its own
Protein and carbohydrates each contain 4 kcal per gram, while fat contains 9 kcal per gram — over twice the energy density.
Protein has a thermic effect of 20–30% (Westerterp, 2004), against 5–10% for carbohydrate and 0–3% for fat — roughly a quarter of protein calories are burned during digestion itself.
The US RDA for protein is 0.8 g per kg of body weight a day; the WHO/FAO/UNU safe level is 0.83 g/kg, enough for 97.5% of healthy adults.
The ISSN's 2017 position stand puts 1.4–2.0 g of protein per kg a day as sufficient for most people who exercise, and up to 2.3–3.1 g/kg for resistance-trained people in a calorie deficit.
Ketogenic diets usually hold carbohydrate under 50 g a day (Paoli et al., 2013) — 200 kcal, or 10% of a 2,000 kcal day.
The adult reference range for fat is 20–35% of energy; the Low Carb and Keto presets here, at 60% and 75%, sit above it by design.
Adults have a carbohydrate RDA of 130 g a day; a 5% keto split at 2,000 kcal provides about 25 g.
During events longer than 2.5 hours, endurance athletes may benefit from up to 90 g of carbohydrate an hour (Burke et al., 2011).
A 2004 WHO expert consultation found high diabetes and cardiovascular risk in a substantial share of Asian people at BMIs below 25.
Mifflin-St Jeor, the equation behind the calorie target, was fitted to 498 healthy adults aged 19–78.
Frequently Asked Questions
-
Macros (macronutrients) are the three main categories of nutrients that provide energy: protein, carbohydrates, and fat. Protein and carbs each provide 4 kcal per gram; fat provides 9 kcal per gram. Tracking your macro intake — not just total calories — gives you control over body composition, energy levels, and training performance.
-
The US RDA is 0.8 g/kg of body weight a day (the WHO/FAO/UNU safe level is 0.83 g/kg). If you train regularly, the ISSN's 2017 position stand puts 1.4–2.0 g/kg as sufficient for most people, and 2.3–3.1 g/kg may be needed to keep lean mass in resistance-trained people during a calorie deficit. This calculator sets protein as a percentage of your calorie target, so the grams depend on your target; the result tells you what your split comes to in g/kg and where that sits against those ranges. To anchor protein to body weight directly, use our body-weight macro calculator, which lets you set protein in grams per kilogram.
-
A standard ketogenic diet is roughly 70–75% fat, 20–25% protein and about 5% carbohydrate; reviews describe carbohydrate held usually under 50 g a day (Paoli et al., 2013). Select the "Keto" preset in this calculator for a 75/5/20 (fat/carbs/protein) macro split. Note that keto is challenging to sustain in Singapore's hawker-centric food culture — see the guide above for practical adaptations.
-
Carb cycling alternates between high-carb days (around training sessions or races) and lower-carb days (on rest or recovery days). It aims to optimise performance and fat loss simultaneously. Use this calculator on both a high-carb and low-carb day to establish your two different macro targets, then alternate based on your training schedule.
-
Neither is a clinical term. "Clean" keto builds the ketogenic split from whole foods (avocado, eggs, fatty fish, nuts); "dirty" keto hits the same numbers with processed food. A macro calculator cannot tell them apart: the grams are identical, and the difference is everything the grams do not measure, such as fibre, micronutrients and saturated fat.
-
We do not rank them. What matters is that the app lets you enter custom gram targets and that its food database covers what you actually eat, including local hawker dishes — check a few of your regular meals before committing. Use this calculator to generate the targets, then enter them into whichever app you prefer.
-
A calorie calculator gives you a single daily energy target (TDEE). A macros calculator goes further — it splits that calorie target into specific gram targets for protein, carbohydrates, and fat based on your goal and chosen diet style. This is more actionable for body composition because each macronutrient has a distinct effect on muscle gain, fat loss, and hormonal balance.
-
Yes — select "Custom" in the Diet Style dropdown. Three input fields will appear for Protein %, Carbs %, and Fat %. They must sum to exactly 100%. This is useful if a registered dietitian or sports coach has prescribed a specific macro split that differs from the presets.
-
The ISSN's position stand says higher intakes, 2.3–3.1 g/kg, may be needed to keep lean mass in resistance-trained people during a calorie deficit, and Westerterp's review links protein's thermic effect to satiety. On this page a deficit shrinks the calorie target, so the same percentage gives fewer grams: check the g/kg line under the result, and raise the protein share (Custom) if it has fallen below where you want it.
-
100% free, forever. No account, no subscription, no hidden limits. All calculations run entirely in your browser — no data is sent to any server. RECATOOLS is funded by contextual advertising, not paywalls. The tool works with or without ad consent enabled.
Method & sources
How it computes
BMR by Mifflin-St Jeor (10 × kg + 6.25 × cm − 5 × age, +5 men / −161 women) × activity factor 1.2-1.9, then −500 / 0 / +300 kcal by goal, shown even when low and flagged under NICE NG246's 1,200 / 800 kcal lines. The target is split by preset or custom percentages; grams = kcal ÷ 4, 4, 9, rounded once, kcal = grams × 4, 4, 9. Protein is reported in g/kg against the 0.8 RDA and ISSN 1.4-2.0; shares against the adult AMDR (EnergyNeedsKernel).
What this tool implements
- Resting energy expenditure: Mifflin-St Jeor equation (Am J Clin Nutr 1990), adults 18-100, with ages outside the study's 19-78 noted.
- Acceptable Macronutrient Distribution Ranges for adults 19+: protein 10-35%, carbohydrate 45-65%, fat 20-35% of energy; carbohydrate RDA 130 g/day (National Academies, as tabled in Dietary Guidelines for Americans 2020-2025, Appendix 1). A split outside them is computed and flagged, not refused.
- Protein: RDA 0.8 g/kg/day; 1.4-2.0 g/kg/day sufficient for most exercising individuals; 2.3-3.1 g/kg/day may be needed to retain lean mass in resistance-trained people during a deficit (ISSN position stand, 2017). WHO/FAO/UNU safe level 0.83 g/kg/day (TRS 935, 2007).
- Low intake: NICE NG246 (2025) 1.16.8-1.16.9 place 800-1,200 kcal/day and under-800 kcal/day diets within specialist services; a loss target under either line is shown and flagged, the same rule as /tdee-calculator/ and /calorie-calculator/.
- Diet-induced thermogenesis: reported values 20-30% protein, 5-10% carbohydrate, 0-3% fat, about 10% of energy ingested on a mixed diet (Westerterp 2004).
- Corrected 2026-10-16: imperial weight read from the metric field; both unit groups shown at once; target silently floored at 1,200 kcal; under-18s accepted; custom splits rounded to 100%; macro kcal rounded apart from grams; High Protein preset 21/44/35 (carbohydrate under the AMDR) → 21/45/34; unsourced Athletic Performance goal (+200 kcal) removed; "WHO recommends 0.8 g/kg" → US RDA 0.8 and WHO/FAO/UNU 0.83; "50 g is ~5% of 2,000 kcal" → 10%; "fat below 20% suppresses hormones", food protein per 100 g, laksa and nasi lemak figures, IRONMAN 6-10 g/kg, retailer and app-popularity claims and a figure-bearing pull-quote removed or replaced by sourced statements; the "every preset capped at 2.0 g/kg" claim replaced by the g/kg the page now computes.
Sources
- Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr 1990;51(2):241-7. PMID 2305711
- US Department of Agriculture and US Department of Health and Human Services. Dietary Guidelines for Americans, 2020-2025, Appendix 1: Nutritional Goals for Age-Sex Groups (AMDR and carbohydrate RDA). https://www.dietaryguidelines.gov/sites/default/files/2020-12/Die…
- Jäger R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition Position Stand: protein and exercise. J Int Soc Sports Nutr 2017;14:20. PMID 28642676; full text https://pmc.ncbi.nlm.nih.gov/articles/PMC5477153/
- WHO/FAO/UNU. Protein and amino acid requirements in human nutrition. WHO Technical Report Series 935, 2007 (safe level 0.83 g/kg/day). https://iris.who.int/handle/10665/43411
- National Institute for Health and Care Excellence. Overweight and obesity management (NG246), 2025, recommendations 1.16.8-1.16.9. https://www.nice.org.uk/guidance/ng246/chapter/Physical-activity-…
- Westerterp KR. Diet induced thermogenesis. Nutr Metab (Lond) 2004;1(1):5. PMID 15507147; full text https://europepmc.org/article/PMC/PMC524030
- Paoli A, Rubini A, Volek JS, Grimaldi KA. Beyond weight loss: a review of the therapeutic uses of very-low-carbohydrate (ketogenic) diets. Eur J Clin Nutr 2013;67(8):789-96. PMID 23801097
- Burke LM, Hawley JA, Wong SH, Jeukendrup AE. Carbohydrates for training and competition. J Sports Sci 2011;29 Suppl 1:S17-27. PMID 21660838
Abridged — the full review record for this tool runs longer than the list above.
Pick up where you left off
Stored only in this browser — never sent to our servers.