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Macro calculator
Daily calories plus protein, carb, and fat targets for losing, maintaining, or gaining, from the Mifflin-St Jeor equation, with the safety clamps shown instead of hidden. Every number checks out on a calculator.
For adults 18 and up. Goal-based calorie planning (deficits and surpluses) is designed for adult bodies, and teens' needs are different. We don't plan weight-change targets for anyone under 18.
Goal
Safe planning band: 0.25-1% of bodyweight per week. We clamp anything outside this range and show the adjustment.
The raw math lands at 1,717 kcal, below the 1,800 kcal adult female safety floor. So your target holds at 1,800 kcal. We don't plan under-eating weeks, so your real deficit is 264 kcal/day, not the 347 kcal that pace implies.
The math, step by step
1 · BMR (Mifflin-St Jeor): 10×63.05 + 6.25×165.1 − 5×34 − 161 = 1,331.4
2 · TDEE = 1,331.4 × 1.55 = 2,064 kcal
3 · Lose 0.5%/week = 63.05 kg × 0.5% = 0.32 kg/week × 7,700 kcal/kg ÷ 7 days = −347 kcal/day
4 · Safety floor: 2,064 − 347 = 1,717 is below the 1,800 kcal adult female floor → target held at 1,800 kcal
5 · Protein: 2.2 g/kg × 63.05 kg = 139 g (556 kcal), the Cut preset, which protects muscle in a deficit (Morton 2018, upper 95% CI)
6 · Remaining 1,800 − 556 = 1,244 kcal → 50% carbs = 156 g, the rest fat = 69 g (4 · 4 · 9 kcal per g)
✓ Check: 139×4 + 156×4 + 69×9 = 1,801 kcal . Grams are rounded to whole numbers, so this can drift a few kcal from the target
These are planning estimates, not clinical prescriptions. Talk to a professional before dietary changes for a medical condition.
How this calculator works
- 01Your BMR comes from Mifflin-St Jeor (the resting-energy equation dietitians default to) and your TDEE from the standard activity multipliers, the same math as our TDEE calculator.
- 02Your goal sets the calorie adjustment: bodyweight × weekly rate × ~7,700 kcal/kg ÷ 7 days. The rate is clamped to the 0.25-1%/week safe band, and the target never goes below the 2,000/1,800 kcal adult floors; when either clamp fires, the calculator says so.
- 03Protein is set in g/kg bodyweight by goal (2.2 losing · 1.2 maintaining · 2.0 gaining), then the remaining calories split into carbs and fat at 4 · 4 · 9 kcal per gram.
Sources: Mifflin-St Jeor, Am J Clin Nutr 1990 · Academy of Nutrition and Dietetics systematic review, J Am Diet Assoc 2005 · Helms et al. 2014, JISSN · Morton et al. 2018, Br J Sports Med · Jäger et al. 2017, JISSN (ISSN position stand) · ~7,700 kcal/kg energy-balance approximation. Planning estimates, not clinical prescriptions.
Common questions
- How are the macros split?
- Protein is set first, in grams per kilogram of bodyweight, because it helps protect muscle. The calories left after protein are split between carbs and fat by ratio, at 4 kcal per gram of protein and carbs and 9 per gram of fat. The calculation chain above shows the exact split used for your numbers.
- Why is protein higher when losing than when maintaining?
- In a calorie deficit, higher protein intake helps preserve lean mass, and the deeper the deficit, the more protein matters (Helms 2014). This calculator uses 2.2 g/kg for weight loss (the upper bound of the Morton 2018 meta-analysis, with a 95% CI ceiling of 2.20 g/kg bodyweight), 2.0 g/kg for gaining (the top of the ISSN 1.4-2.0 g/kg band), and a 1.2 g/kg planning baseline for maintenance.
- What are the safety clamps?
- Two, both shown when they fire rather than silently applied. The weekly rate is clamped to 0.25-1% of bodyweight per week; faster than 1% mostly costs muscle and adherence. And the calorie target never drops below 2,000 kcal for men or 1,800 kcal for women. We don't plan under-eating weeks.
- Where does the calorie adjustment come from?
- From the ~7,700 kcal per kilogram energy-balance approximation: your bodyweight × weekly rate gives kilograms per week, × 7,700 gives weekly calories, ÷ 7 gives the daily deficit or surplus. It is a planning heuristic, not a law of physics. Real-world results drift, so adjust from what the scale does over a few weeks.
Just want maintenance? The free TDEE calculator shows your BMR and maintenance calories at every activity level.