Macro Calculator — Protein, Fat & Carb Targets
Split your daily calories into protein, fat and carbohydrate targets built on published intake ranges.
- Nutrition
- 2 cited sources
- Runs in your browser
Your estimated daily macros
| Macro | Grams/day | kcal/day |
|---|---|---|
| Protein | 144 g | 576 |
| Fat | 69 g | 625 |
| Carbohydrate | 325 g | 1,299 |
These are estimated planning targets, not prescriptions — staying within 5–10 g of each is plenty accurate for most goals.
Methodology
This calculator builds your macro targets in three steps, in a deliberate order:
- Protein is set first, from bodyweight: your chosen intake between 1.6 and 2.2 g per kilogram per day. The default of 1.8 g/kg sits in the middle of the range supported by the largest systematic review on the topic (Morton et al., 2018), which found muscle-building benefits plateau at around 1.6 g/kg, with a margin above for dieting or heavy training.
- Fat is set as a share of your calorie target, between 20% and 35% — the acceptable macronutrient distribution range from the Institute of Medicine's Dietary Reference Intakes.
- Carbohydrate fills whatever calories remain.
Grams and calories convert using the standard Atwater factors:
protein 4 kcal/g · carbohydrate 4 kcal/g · fat 9 kcal/g
Nothing is rounded until display, so the three macros always sum to your calorie target when the split is feasible.
Interpreting your result
Treat the output as a planning template rather than a daily contract. Protein is the number worth hitting most consistently — it drives muscle retention while dieting and growth while gaining. Fat and carbohydrate can flex against each other according to preference: neither split has been shown to meaningfully outperform the other for fat loss when calories and protein are matched.
If the calculator warns that your split is infeasible, your protein and fat settings already exceed the calorie target — something has to give, and it is usually the calorie target that is set too low.
Limitations
- The Atwater factors are averages across foods; the true energy you absorb varies with food choice, fibre and processing by a few percent.
- Protein recommendations here are aimed at people who train. Sedentary adults need less (the UK reference nutrient intake is 0.75 g/kg), while very lean athletes in a deficit may benefit from the top of the range.
- Calorie targets are only as good as the estimate behind them — pair this tool with the TDEE calculator and adjust from real-world results.
Sources
Pull the receipts — 2 cited sources
FitTools · sources
- 01 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 and strength. Br J Sports Med 2018;52:376–384
- 02 Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (2005) — fat AMDR 20–35% of energy
Every formula cited ✓
Frequently asked questions
- How much protein should I eat to build muscle?
- A 2018 systematic review of 49 trials found that benefits for muscle growth plateau around 1.6 g of protein per kilogram of bodyweight per day, with roughly 2.2 g/kg as a sensible upper bound during a diet. This calculator defaults to 1.8 g/kg, in the middle of that evidence-based range.
- How is the calorie split calculated?
- Protein is set first from your bodyweight, fat is set as a percentage of your calorie target (20–35%), and carbohydrate fills the remaining calories. Grams are converted using the standard Atwater factors: 4 kcal per gram for protein and carbohydrate, 9 kcal per gram for fat.
- Why do my macros not add up to my calorie target elsewhere?
- Different calculators use different protein rules and rounding. This tool keeps the arithmetic exact until display, so protein, fat and carbohydrate calories always sum to your target when the split is feasible.
- Do I need to hit these numbers exactly?
- No. Macro targets are planning aids, not prescriptions. Staying within roughly 5–10 g of each target day to day is more than accurate enough for body-composition goals.
- What calorie target should I use?
- Start from your estimated maintenance calories — our TDEE calculator will give you that — then adjust down for fat loss or up for muscle gain before splitting into macros.
Written and reviewed by Mathew Beale — MSc Biotechnology, University of Reading.
Last reviewed:
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