Macro Calculator
Get your personalised daily calories & macronutrient targets in seconds.
Use the macro calculator above to get your personalised daily calories and macronutrient targets in seconds. Enter your profile details, activity level, and fitness goal — the tool instantly calculates how many calories, grams of protein, carbs, and fats you need each day to lose fat, maintain weight, or build muscle. Whether you are starting a new diet plan, training for an event, or simply want to eat smarter, this free online macro calculator gives you a clear, science‑backed nutrition blueprint.
Below you will find a complete step‑by‑step guide to using the macro calculator, an explanation of the formulas it uses, examples for different fitness goals, macronutrient reference tables, and answers to common questions about macros.
How to Use the Macro Calculator
The macro calculator walks you through a simple 3‑step wizard — Profile → Activity → Goal. Each step takes only a few seconds to complete, and the final result gives you a complete daily nutrition plan.
- Step 1 – Profile: Select your biological sex (Male or Female), enter your age in years, choose your preferred unit system (Metric — cm/kg, or Imperial — ft/lbs), and enter your height and weight. These inputs are essential because they form the foundation of the Basal Metabolic Rate (BMR) calculation.
- Step 2 – Activity: Choose your typical daily activity level — Sedentary, Lightly Active, Moderately Active, Very Active, or Extra Active. Be honest here; overestimating activity is the most common reason people see slow progress. Your activity multiplier converts BMR into Total Daily Energy Expenditure (TDEE).
- Step 3 – Goal: Pick your goal — Lose Fat, Maintain Weight, or Build Muscle. The calculator adjusts your calorie target with a sensible deficit or surplus and distributes calories across protein, carbs, and fats based on evidence‑based ratios.
- Click “Calculate” — The macro calculator instantly displays your daily calorie target along with grams of protein, carbohydrates, and fats. Use these numbers to plan your meals, track intake with a food‑logging app, and review your results.
What Are Macros and Why Do They Matter?
“Macros” is short for macronutrients — the three nutrients your body needs in large amounts to function and fuel daily activity:
- Protein (4 kcal/g) — Builds and repairs muscle, supports immune function, and keeps you full. Essential for anyone training, dieting, or recovering from injury.
- Carbohydrates (4 kcal/g) — Your body’s preferred fuel source, especially for the brain and high‑intensity exercise. Carbs power your workouts and replenish glycogen.
- Fats (9 kcal/g) — Supports hormone production, vitamin absorption, brain health, and long‑duration energy. Dietary fat is essential, not optional.
Counting calories alone tells you how much you are eating, but tracking macros tells you what you are eating. Two diets at 2,000 calories can produce very different results depending on their macronutrient split — which is exactly why a macro calculator is more useful than a simple calorie counter.
The Formulas Behind the Macro Calculator
The macro calculator uses well‑established nutrition science. Here are the three core steps:
1. Basal Metabolic Rate (BMR) — Mifflin‑St Jeor Equation
Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
2. Total Daily Energy Expenditure (TDEE)
| Activity Level | Multiplier | Description |
|---|---|---|
| Sedentary | 1.2 | Little to no exercise, desk job |
| Lightly Active | 1.375 | Light exercise 1–3 days/week |
| Moderately Active | 1.55 | Moderate exercise 3–5 days/week |
| Very Active | 1.725 | Hard exercise 6–7 days/week |
| Extra Active | 1.9 | Physical job + daily training |
3. Goal‑Based Calorie Adjustment
| Goal | Calorie Target |
|---|---|
| Lose Fat | TDEE − 20% (≈ 500 kcal deficit) |
| Maintain Weight | TDEE (no change) |
| Build Muscle | TDEE + 10–15% (≈ 250–400 kcal surplus) |
Worked Example — Male, 25, 175 cm, 70 kg
Let’s run the default profile from the macro calculator through the formulas:
- BMR = (10 × 70) + (6.25 × 175) − (5 × 25) + 5 = 700 + 1093.75 − 125 + 5 = 1,673.75 kcal
- TDEE (Moderately Active, ×1.55) = 1,673.75 × 1.55 ≈ 2,594 kcal
- Maintenance calories ≈ 2,594 kcal/day
Goal
Maintain
Calories
2,594
Protein
140 g
Carbs
325 g
Fats
72 g
Recommended Macro Splits by Goal
Different goals call for different macro ratios. The macro calculator applies these evidence‑based splits automatically:
| Goal | Protein | Carbs | Fats |
|---|---|---|---|
| Lose Fat | 35–40% | 30–35% | 25–30% |
| Maintain Weight | 25–30% | 40–50% | 25–30% |
| Build Muscle | 25–30% | 45–55% | 20–25% |
Tips for Hitting Your Macros Consistently
- Prioritise protein first. Hit your protein target every day — it is the hardest macro to get and the most important for muscle and satiety.
- Use a food‑tracking app. Tools like MyFitnessPal, Cronometer, or MacroFactor make logging painless and accurate.
- Meal‑prep on weekends. Pre‑portioned meals remove guesswork during busy weekdays.
- Don’t fear repetition. Eating similar meals daily makes macro targets predictable and easier to hit.
- Adjust based on results. If you are not losing/gaining as expected after 2–3 weeks, recalculate with the macro calculator and tweak intake by 10%.
Frequently Asked Questions
What is a macro calculator?
A macro calculator is a free online tool that calculates your daily calorie target and the optimal grams of protein, carbohydrates, and fats based on your age, sex, height, weight, activity level, and fitness goal. It uses the Mifflin‑St Jeor BMR equation combined with activity multipliers and goal‑specific calorie adjustments.
How accurate is the macro calculator?
The macro calculator uses the Mifflin‑St Jeor equation, which is one of the most accurate BMR formulas validated in published research. However, individual metabolism varies. Use the calculator’s output as a starting point and adjust based on real‑world results after 2–3 weeks.
How much protein should I eat per day?
For most active adults, 1.6–2.2 grams of protein per kilogram of body weight is ideal for muscle building or fat loss. Sedentary adults need around 0.8 g/kg. The macro calculator handles this automatically based on your goal.
Can I use the macro calculator to lose weight?
Yes. Select “Lose Fat” in Step 3. The calculator applies a moderate calorie deficit (~20% below TDEE) and increases your protein ratio to preserve muscle while losing fat.
Should I count macros or just calories?
Calories determine weight change, but macros determine body composition. If your goal is fat loss with muscle retention, muscle gain, or athletic performance, tracking macros gives much better results than calories alone.
How often should I recalculate my macros?
Recalculate every 4–6 weeks or after every 2–3 kg of weight change. Your body adapts as you lose or gain weight, so updated targets keep your progress steady.
Does the macro calculator save my data?
No. All calculations happen locally in your browser. Your profile and results are never stored, shared, or sent to a server.
Is this calculator suitable for vegetarians or vegans?
Yes. The macro targets work for any diet style. Vegetarians and vegans simply need to focus on protein‑rich plant foods like tofu, tempeh, lentils, beans, seitan, and pea/soy protein powders to hit their protein number.
External Resources
- National Institutes of Health — Authoritative guidance on nutrition and dietary requirements.
- Academy of Nutrition and Dietetics — Find a registered dietitian and read evidence‑based nutrition articles.
- Examine.com — Independent, research‑based analysis of supplements and nutrition topics.
- Basal Metabolic Rate – Wikipedia — Detailed explanation of BMR and the equations used to calculate it.