Cutting Macros Calculator
Get calorie, protein, fat and carb targets for a fat-loss cut: enter your maintenance calories or estimate them, set the deficit as a percentage or a weekly loss rate, base protein on body weight or lean mass, and see weekly loss, time to your goal weight and macros per meal.
How it works
Target calories = TDEE × (1 − deficit %), or TDEE − weight × weekly rate % × 7,700 kcal/kg ÷ 7 · TDEE (if estimated) = Mifflin-St Jeor BMR × activity factor · protein = body weight × g/kg (default 2.0) or lean mass × g/kg · fat = fat share × calories ÷ 9 (default 25%) · carbs = (calories − protein × 4 − fat × 9) ÷ 4 · weekly loss ≈ daily deficit × 7 ÷ 7,700 kcal/kg
A cut runs a moderate calorie deficit while keeping protein high so that most of the weight lost is fat rather than muscle. Enter your maintenance calories (TDEE) or let the calculator estimate them with the Mifflin-St Jeor equation and an activity factor; estimated targets are not taken below 1,200 kcal a day for women or 1,500 for men. Set the deficit as a share of maintenance or as a weekly loss rate in percent of body weight — 0.5–1% a week is the range most often recommended for keeping muscle. Protein defaults to 2 g per kg of body weight; if you carry a lot of body fat, base it on lean mass instead. Fat is a share of calories (25% by default) and carbohydrates fill the rest. The calculator also estimates your weekly loss from the 7,700 kcal-per-kg rule of thumb, the time to reach a goal weight with a week-by-week projection, macros per meal and the targets at other deficit sizes.
Worked example
On a 2,500 kcal TDEE with a 20% deficit at 80 kg: 2,000 kcal a day (a 500 kcal deficit), 80 × 2 = 160 g protein, 2,000 × 25% ÷ 9 = 56 g fat and (2,000 − 640 − 500) ÷ 4 = 215 g carbs. The deficit works out at about 500 × 7 ÷ 7,700 = 0.45 kg a week (0.57% of body weight), so getting from 80 to 72 kg takes about 18 weeks. Over 4 meals that is 40 g protein, 14 g fat and 54 g carbs each.
Sources: Helms ER et al. (2014) — Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation · Jäger R et al. (2017) — ISSN position stand: protein and exercise · Mifflin MD et al. (1990) — A new predictive equation for resting energy expenditure
Frequently asked questions
How big should the deficit be?
10–20% of maintenance, or 0.5–1% of body weight a week, is sustainable for most people. Larger deficits lose weight faster but are harder to stick to and risk more muscle loss, especially if you are already lean.
How much protein do I need on a cut?
About 1.6–2.4 g per kg of body weight a day (0.7–1.1 g per lb) for most people who train. Lean lifters in a deep deficit may go up to 2.3–3.1 g per kg of lean mass; people with a lot of body fat can base the target on lean mass so it does not come out unrealistically high.
Do I need to hit macros exactly?
Protein and total calories matter most. Fat and carbs can flex around your preferences and training, as long as fat does not drop too low for long.
Why is my weight loss slower than the calculator says?
The 7,700 kcal-per-kg figure is an average, water weight hides fat loss for days at a time, and maintenance calories drop as you get lighter. Judge progress on a 2–3 week average and recalculate every few kilos.
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General educational estimate, not medical advice. Individual needs vary — talk to a doctor or registered dietitian for personal guidance.