Macro Calculator
Last updated: June 2026 · Free · No sign-up required
Enter values above and click Calculate to see your result instantly.
Quick reference
Common macro splits (% of calories):
| Goal | Protein | Carbs | Fat |
|---|---|---|---|
| Balanced | 30% | 40% | 30% |
| Low-carb | 40% | 20% | 40% |
| High-carb / endurance | 25% | 55% | 20% |
monitor_weight A starting point, not a diagnosis
This calculator gives you the same number a clinician would compute by hand from your inputs. It is informational, never a substitute for a doctor. If a result surprises you, write it down and discuss it at your next appointment — that conversation is the goal, not a verdict from a webpage.
science Built from peer-reviewed formulas
Every health calculator on CalcaTools uses an equation from the WHO, NIH, ACOG, CDC, or a published peer-reviewed paper. The exact citation is in the "Formula & methodology" section. We re-check sources quarterly and update the page when guidance changes — the "Last reviewed" date is at the top.
volunteer_activism Designed for real people
Health calculations only help if you can actually use them. We use plain-English labels (no jargon), accept both metric and US units, and show what a "normal" range looks like alongside your result — so you understand what the number means, not just what it is.
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Your weight, height, age, pregnancy details, and any other health input never leave your browser. Calculations run client-side; nothing is logged or stored on our side. We don't want your medical data — we just want the formula to work for you.
Interpretation guide
Calories per gram:
| Macronutrient | Calories/gram |
|---|---|
| Protein | 4 |
| Carbohydrate | 4 |
| Fat | 9 |
| Alcohol | 7 |
Formula & methodology
Formula: Grams = (calories x macro%) / calories-per-gram (4 protein, 4 carb, 9 fat)
The calculator starts from your daily calorie target (or TDEE adjusted for your goal), then divides it among protein, carbohydrate, and fat using your chosen ratio. Each gram of protein and carbs supplies 4 calories and fat supplies 9, so the grams follow directly. Protein is usually set first to preserve muscle (often 0.7–1 g per pound of body weight), with carbs and fat filling the rest based on preference and performance.