Macro calculator
Most macro calculators are protein-as-a-percentage. We anchor protein in g/kg of bodyweight (the only ratio backed by sports-nutrition meta-analyses), set fat at a safe floor, and let carbs absorb the rest. Built for fat loss, lean bulks, or maintenance — not for selling you a meal plan.
- Protein target from peer-reviewed g/kg (Phillips, Helms, Morton)
- Carbs & fat fill the remaining calories around your protein floor
- Per-meal split clears the leucine threshold each time
How this calculator works
We compute macros in this order, which is the convention used in evidence-based sports nutrition:
- TDEE via the Mifflin-St Jeor equation (Frankenfield et al. 2005), then adjust for goal: −20% for fat loss, 0% for maintenance, +10% for a lean bulk (Iraki et al. 2019, Sports — minimises fat gain while still supporting hypertrophy).
- Protein in g/kg of bodyweight, goal-dependent: 1.2–1.6 maintain (Phillips & Van Loon 2011), 1.6–2.2 lose fat (Helms et al. 2014), 1.6–2.2 build muscle (Morton et al. 2018 meta-analysis).
- Fat at a g/kg floor: 0.8 in a deficit, 1.0 at maintenance and on a bulk — the ISSN Position Stand on Diets safe range for hormonal function (Aragon et al. 2017).
- Carbs fill the remaining calories. They are the most flexible macro: scale up if you train hard, scale down if you do not.
All gram outputs are rounded to the nearest 5g for usability — kitchen scales and food labels do not justify finer precision. For the full math, citations, and edge cases, see the methodology page →
Frequently asked questions
The questions people actually search before they pick a macro split.
How do I split my macros for fat loss?
Anchor protein first (1.6–2.2 g/kg of bodyweight) to preserve muscle, set fat at a 0.8 g/kg floor for hormonal function, then let carbs absorb the remaining calories in a ~20% deficit. Cutting too much fat or carbs while keeping calories the same will not speed fat loss — only a calorie deficit drives the loss. The protein and fat floors protect what you keep.
What ratio of carbs to fat is best?
There is no single "best" ratio — once protein and a 0.6–1.0 g/kg fat floor are met, the carb-to-fat split is mostly a preference and performance question. People who train hard generally do better with more carbs (faster recovery, better lifts). Lower-carb splits suit people who feel better with steadier blood sugar. We default to protein + 0.8–1.0 g/kg fat + carbs as the remainder because it works for most goals.
Should I track macros or just protein?
For most people, hitting a daily protein target (in grams) and staying near maintenance calories does ~80% of the work. Full macro tracking helps when you have a specific performance or physique goal — a powerlifter timing carbs around training, a bodybuilder in a contest cut, or someone troubleshooting why a deficit is not producing fat loss. If you are just starting out: start with protein only, add the others once protein is consistent for 2–4 weeks.
How many calories below maintenance should I eat to lose fat?
A 15–25% deficit is the standard recommendation — large enough to drive measurable weekly loss (about 0.5–1% of bodyweight per week), small enough to preserve performance, training adherence, and lean mass. We use 20% by default. Aggressive cuts (>30%) tend to backfire through binge eating, muscle loss, and metabolic adaptation.
Why does this calculator give a higher protein target than older calculators?
The RDA of 0.8 g/kg is a deficiency-prevention minimum from the 1980s. The current sports-nutrition consensus for body composition is 1.6–2.2 g/kg, supported by Morton et al. 2018 (a meta-analysis of 49 studies). Most "online macro calculators" still use protein percentages (e.g. 30% of calories), which collapses to under 1 g/kg for many people in a deficit. We anchor protein in g/kg, not as a calorie %.