Macros Calculator
Get your daily protein, carbs, and fat in grams. Goal-based presets for cutting, maintenance, and lean bulk. Built on Mifflin-St Jeor with high-protein splits backed by research.
Daily macros
On your plate, across 4 meals a day
These are rough hand-portion estimates. The grams in the cards above are what matters, the per-meal numbers just help you eyeball it.
Want a 12-week trajectory chart and goal-by-goal calorie targets in one place? Use the full TDEE Calculator.
How this macros calculator works
Macros (short for macronutrients) are the three energy-containing parts of food: protein, carbohydrate, and fat. Hitting the right total calories gets your weight where you want it; hitting the right macro split gets your body composition where you want it. This calculator does both in four steps.
A useful way to think about macros: calories are the speed limit, macros are the steering wheel. Calories alone determine whether you gain, lose, or maintain weight. Macros determine what kind of weight, muscle or fat, and how you feel while doing it. Two people eating the same 2,200 calories with very different splits (say 60% carbs versus 50% fat) will end up at the same body weight but with different physiques and different gym performance.
Step 1, Calculate TDEE
First we estimate your total daily burn using Mifflin-St Jeor:
- Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
- Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
Then BMR × activity multiplier = TDEE. If you provide body fat %, we use Katch-McArdle (BMR = 370 + 21.6 × lean mass) for higher accuracy.
Step 2, Adjust calories for your goal
- Cutting: TDEE × 0.80 (a 20% deficit, sustainable and protein-friendly)
- Maintenance: TDEE × 1.00
- Lean Bulk: TDEE × 1.10 (a 10% surplus, slow enough to limit fat gain)
Step 3, Apply the macro split
Each goal uses a different split because the body has different priorities. The numbers below are protein/carbs/fat as a percentage of total calories:
- Cutting (40 / 35 / 25): Protein is pushed high to preserve muscle in a deficit. Research consistently shows 1.6-2.2 g/kg protein protects lean mass during weight loss; the 40% split lands inside that range for most people.
- Maintenance (30 / 45 / 25): A balanced default. Plenty of protein, plenty of carbs to fuel training, fat held to the lower end of healthy.
- Lean Bulk (30 / 50 / 20): Carbs are pushed up to fuel hard training and replenish glycogen between sessions. Protein stays at 30% (still ~1.6 g/kg or higher in absolute terms because total calories are higher), fat is trimmed to make room for carbs.
Step 4, Convert calories to grams
Each macro has a fixed energy density. These three numbers are the foundation of every macro calculation:
- Protein: 4 kcal per gram
- Carbs: 4 kcal per gram
- Fat: 9 kcal per gram
So if your cut puts you at 2,000 kcal with a 40/35/25 split:
- Protein = 2,000 × 0.40 ÷ 4 = 200 g
- Carbs = 2,000 × 0.35 ÷ 4 = 175 g
- Fat = 2,000 × 0.25 ÷ 9 = 56 g
Why protein gets prioritized in a cut
In a calorie deficit, your body breaks down stored energy. You want that to be fat, not muscle. Three factors protect muscle: resistance training, adequate protein, and a moderate (not crash) deficit. Protein at 1.6-2.2 g/kg has been shown across multiple meta-analyses to be the threshold above which extra protein offers no additional benefit for muscle retention. Below that, lean mass loss accelerates. The 40% split for cutting is engineered to land you in that zone.
Protein has a second benefit during a cut, it is the most filling macro. Studies on satiety consistently rank protein well above carbs and fat at matching calorie loads. A 600-calorie meal heavy in protein leaves most people fuller four hours later than a 600-calorie meal heavy in fat. When you are running a 500-calorie daily deficit and food has to feel adequate, this is not a small advantage.
Why carbs get pushed up on a bulk
Carbs refill muscle glycogen, which is the dominant fuel source for resistance training and high-intensity work. A glycogen-depleted lifter loses strength, recovers slower, and trains less productively. On a lean bulk you also have an easy mandate: gain muscle. Carbs are cheap calories, they spare protein from being burned for fuel, and they do not blunt training output. The 50% carb share for the bulk preset is calibrated to support 4-6 quality training sessions a week without packing on extra fat.
Why fat does not drop below 20%
Fat is essential for hormone production (testosterone, estrogen) and the absorption of fat-soluble vitamins (A, D, E, K). Diets that drop below about 20% of calories from fat for extended periods are associated with low libido, mood issues, and disrupted menstrual cycles. The 25% floor on cutting and maintenance, and the 20% floor even on a lean bulk, keeps you safely above that line.
Accuracy
Macros calculators are estimates of estimates, the TDEE is an estimate, the macro splits are population averages. Treat the gram targets as a starting point. If you are not progressing after two to three weeks of hitting them consistently, adjust calories first (by 100-200), then revisit the split.
Hitting macros within ±5 grams per day is plenty close. Chasing exact numbers down to the gram is a recipe for disordered eating without much extra body composition payoff. The point of tracking is to get you in the right neighborhood consistently, not to turn dinner into a chemistry experiment.
Sources: Helms ER, et al. A systematic review of dietary protein during caloric restriction. Int J Sport Nutr Exerc Metab. 2014. · Morton RW, et al. A systematic review, meta-analysis, and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass. Br J Sports Med. 2018. · Mifflin MD, et al. 1990.
Frequently asked questions
How much protein should I eat per day?
For most people who train, 1.6-2.2 grams per kilogram of bodyweight (about 0.7-1.0 g per pound) is the research-backed range. The lower end is fine for maintenance; the higher end matters most when cutting, since protein preserves muscle in a deficit. Going above 2.5 g/kg has not been shown to add benefit for muscle retention or growth.
Do women need different macros than men?
The macro ratios (protein, carbs, fat as a percentage of calories) are the same. Total calories differ because women on average have less lean mass and a lower BMR. Per-kg-bodyweight protein recommendations are identical for both sexes. The main practical difference: women hitting 1.8 g/kg protein on a 1,800-calorie cut have to be more deliberate about protein density than a man on a 2,500-calorie cut.
Are carbs at night bad?
No. Total daily calories and macros are what move the scale. Whether you eat your carbs at 7am or 10pm has no measurable impact on body composition. Some people sleep better with a carb-containing dinner, some prefer to front-load. Eat what fits your schedule and hunger.
What is the difference between dirty bulk and lean bulk?
A lean bulk is a small calorie surplus (about 10% above TDEE) that adds roughly 0.5 lb a week, mostly muscle. A dirty bulk is a much larger surplus (sometimes 50%+) that adds weight fast but most of it is fat, which then has to be cut off later. Lean bulk wins for almost everyone outside competitive strength sports.
Can vegans hit these macros?
Yes. The reliable vegan protein sources are tofu, tempeh, seitan, lentils, chickpeas, edamame, and supplemental protein powders (pea, soy, rice). Hitting 1.6-2.2 g/kg as a vegan takes more planning than as an omnivore but is straightforward with daily tofu or legumes plus one protein shake. Some vegans bump protein slightly higher (around 1.8-2.0 g/kg minimum) to account for slightly lower digestibility of plant protein.
What is IIFYM?
IIFYM stands for "If It Fits Your Macros." The idea is that as long as you hit your daily protein, carb, and fat targets, the specific food sources do not matter much for body composition. It works for body comp, but micronutrients, fiber, and satiety still matter, so most of your food should be whole foods even on IIFYM. The flexibility is the point, you can fit ice cream into a cut, you cannot live on it.
Does this calculator store my data?
No. All calculations happen in your browser. Nothing is sent to a server, nothing is stored, no signup is required.