Free Macro Calculator
Calculate your ideal protein, carbs, and fat for weight loss, muscle gain, or maintenance. Science-backed formulas personalized for your body and goals.
How This Calculator Works
The science behind your personalized macro targets
Step 1: Calculate Your BMR
Your Basal Metabolic Rate (BMR) is how many calories your body burns just existing — breathing, pumping blood, maintaining body temperature. We use one of two validated formulas:
Mifflin-St Jeor Equation (Default)
The most accurate BMR formula for most people, according to research[1]:
Men: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5 Women: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161 Katch-McArdle Formula (With Body Fat %)
More accurate for lean individuals and those who know their body fat percentage:
BMR = 370 + (21.6 × lean body mass in kg) Lean body mass = total weight × (1 − body fat %)
Step 2: Determine Your TDEE
Your Total Daily Energy Expenditure (TDEE) is your BMR multiplied by an activity factor. This represents the total calories you burn in a typical day:
| Activity Level | Multiplier | Description |
|---|---|---|
| Sedentary | 1.2 | Desk job, little to no exercise |
| 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 |
| Extremely Active | 1.9 | Athlete or physical job + training |
Step 3: Adjust for Your Goal
To lose fat, you need a calorie deficit. To build muscle, you need a calorie surplus:
- Weight loss: Subtract 250-1000 calories (depending on rate chosen)
- Maintenance: No adjustment — eat at TDEE
- Muscle gain: Add 200-500 calories (we use a conservative surplus to minimize fat gain)
Step 4: Distribute Into Macros
Your total calories are split into protein, carbs, and fat based on your diet style and goals:
- Protein: 4 calories per gram — essential for muscle
- Carbohydrates: 4 calories per gram — primary fuel source
- Fats: 9 calories per gram — hormones and satiety
We adjust protein higher for weight loss (to preserve muscle) and for experienced lifters. Learn more about macros →
Why Use Our Macro Calculator?
Research-Backed Formulas
We use the Mifflin-St Jeor equation — shown in studies to be the most accurate for estimating metabolic rate in healthy adults[1].
Personalized Results
Unlike one-size-fits-all calculators, we adjust for your training experience, health conditions, and specific goals.
Dual Formula Support
Know your body fat %? We automatically switch to the Katch-McArdle formula for more accurate results based on lean mass.
100% Free, No Signup
No email required, no account needed, no upsells. Just calculate your macros and start using them immediately.
Macros in Common Foods
Use this reference to plan meals that hit your macro targets
| Food | Serving | Calories | Protein | Carbs | Fat |
|---|---|---|---|---|---|
| Protein Sources | |||||
| Chicken Breast | 4 oz | 165 | 31g | 0g | 4g |
| Salmon | 4 oz | 233 | 25g | 0g | 14g |
| Eggs | 2 large | 156 | 12g | 1g | 10g |
| Greek Yogurt | 1 cup | 130 | 17g | 8g | 4g |
| Ground Beef (90% lean) | 4 oz | 200 | 23g | 0g | 11g |
| Tofu (firm) | 4 oz | 94 | 10g | 2g | 5g |
| Carb Sources | |||||
| White Rice | 1 cup cooked | 206 | 4g | 45g | 0g |
| Potato | 1 medium | 161 | 4g | 37g | 0g |
| Oatmeal | 1 cup cooked | 166 | 6g | 28g | 4g |
| Banana | 1 medium | 105 | 1g | 27g | 0g |
| Fat Sources | |||||
| Avocado | 1/2 fruit | 161 | 2g | 9g | 15g |
| Olive Oil | 1 tbsp | 119 | 0g | 0g | 14g |
| Almonds | 1 oz (23 nuts) | 164 | 6g | 6g | 14g |
| Peanut Butter | 2 tbsp | 188 | 8g | 6g | 16g |
More Free Nutrition Calculators
Additional tools to support your nutrition and fitness goals
One Rep Max Calculator
Estimate your maximum lift capacity for strength training programming
Meal Macro Calculator
Calculate macros for individual meals or recipes
Walking Calorie Calculator
Calculate calories burned walking based on distance and pace
Protein Calculator
Calculate your daily protein needs based on goals
TDEE Calculator
Calculate your Total Daily Energy Expenditure
BMR Calculator
Calculate your Basal Metabolic Rate
How to Use Your Macro Results
A practical guide to turning these numbers into real progress
Choose a Tracking App
Download a food tracking app and set it to your calculated macros:
- MyFitnessPal — Largest food database, free version works fine
- Cronometer — Most accurate entries, great for micronutrients too
- MacroFactor — Adaptive coaching, adjusts targets automatically
Plan Your Protein First
Protein is the most important macro. Spread it across meals (20-40g per meal for most people). Good sources:
- Chicken, turkey, lean beef, fish
- Eggs, Greek yogurt, cottage cheese
- Tofu, tempeh, legumes
- Protein powder (if needed to hit targets)
Fill In Carbs and Fats
Once protein is planned, add carbs and fats to hit your targets. The balance between them is flexible — personal preference matters most.
- More carbs: Better for performance and recovery
- More fats: Better for satiety and hormones
Track for 2-3 Weeks Before Adjusting
Don't change your macros based on a few days of data. Weight fluctuates due to:
- Water retention (sodium, carbs, hormones)
- Food volume in your system
- Sleep and stress
Track your weekly average weight. If it's not moving in the right direction after 2-3 weeks, adjust by 100-200 calories.
Don't Aim for Perfection
You don't need to hit your macros perfectly every day. Aim for:
- Within ±100 calories of target
- Within ±10g on protein
- Carbs and fats can balance each other
Consistency over weeks matters more than perfection on any single day. Common mistakes to avoid →
Frequently Asked Questions
Everything you need to know about macros and this calculator
Calculator Questions
How accurate is this macro calculator?
Our calculator uses the Mifflin-St Jeor equation — research shows it's the most accurate formula for estimating metabolic rate in most people[1]. If you provide body fat %, we use the Katch-McArdle formula which can be even more accurate for leaner individuals.
That said, all calculators provide estimates. Use your results as a starting point, track for 2-3 weeks, then adjust based on actual results.
Why does my result differ from other calculators?
Different calculators use different formulas and activity multipliers. We use Mifflin-St Jeor (considered the gold standard) with standard activity multipliers. Some calculators use older formulas like Harris-Benedict which tend to overestimate by 5-10%.
Should I use my current weight or goal weight?
Use your current weight. Your macros will be recalculated as you progress. Basing calculations on goal weight often results in too aggressive a deficit that's hard to sustain.
How often should I recalculate?
Recalculate every 10-15 pounds of weight change, or every 4-6 weeks if you're not seeing expected results. As you lose weight, your calorie needs decrease.
What activity level should I choose?
Be conservative — most people overestimate their activity. If you exercise 3-4 times per week but have a desk job, choose "Moderately Active." Only choose "Very Active" if you train intensely 6-7 days per week or have a physical job.
Weight Loss Questions
What's the best macro ratio for weight loss?
For weight loss, prioritize protein (0.8-1g per pound bodyweight) to preserve muscle. A common split is 40% carbs, 30% protein, 30% fat. But the most important factor is the calorie deficit — the macro split is secondary.
Why is protein so high for weight loss?
Higher protein during a calorie deficit helps preserve muscle mass while losing fat. Research shows 0.8-1.2g per pound prevents muscle loss[2]. Protein also increases satiety, making the diet easier to stick to.
Should I eat back exercise calories?
Generally no. The activity multiplier already accounts for your exercise. Eating back calories often leads to overestimating burn and underestimating intake. If you're losing too fast or feel depleted, increase your activity level setting instead.
How fast should I lose weight?
A safe, sustainable rate is 0.5-1% of body weight per week (roughly 1-2 lbs for most people). Faster rates risk muscle loss and are harder to maintain. Choose "Moderate" or "Slow" in the calculator for better long-term results.
Muscle Building Questions
What macros do I need to build muscle?
For muscle gain, you need a calorie surplus (eat more than you burn) plus adequate protein (0.8-1g per pound). A typical split: 40% carbs, 30% protein, 30% fat. Carbs fuel your workouts and support recovery.
Can I lose fat and build muscle at the same time?
Yes — this is called body recomposition. It works best for beginners, those returning after a break, or people with higher body fat. Eat at maintenance or slight deficit, keep protein high, and lift weights consistently. Progress is slower but you achieve both goals.
How big should my calorie surplus be?
A surplus of 200-500 calories is optimal. Larger surpluses just add more fat. Our calculator uses a conservative surplus to minimize fat gain while maximizing muscle growth potential.
Tracking Questions
Do I need to track macros forever?
No. Track strictly for 4-8 weeks to learn portion sizes and develop intuition. After that, many people can maintain results by tracking loosely or just monitoring protein. Think of it as building a skill, not a lifelong requirement.
What's more important — macros or calories?
Calories determine whether you gain or lose weight. Macros determine what kind of weight (muscle vs fat) and how you feel. Both matter, but calories set the foundation. That said, hitting your protein target is usually more important than perfectly balancing carbs and fats.
Do I need to hit my macros exactly?
No — aim for ±5-10g on each macro. Consistency over time matters more than perfection on any single day. If you're over on carbs but under on fat, it roughly balances out calorie-wise.
Special Circumstances
How do macros change for women?
The formula accounts for biological differences. Women may need to pay more attention to fat intake (important for hormones) and may experience more weight fluctuations due to menstrual cycle. Track weekly averages, not daily weight.
Do macros change as I age?
Yes. Metabolism naturally decreases about 1-2% per decade after 20. The calculator accounts for age in the formula. Older adults may also benefit from higher protein to prevent muscle loss.
What about eating out and social events?
You don't need to avoid restaurants. Check nutrition info online beforehand, estimate portions, and don't stress about one meal. Focus on making good choices 80% of the time.
References
- Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990;51(2):241-247. PubMed
- Morton RW, Murphy KT, McKellar SR, 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 in healthy adults. Br J Sports Med. 2018;52(6):376-384. PubMed
- Helms ER, Aragon AA, Fitschen PJ. Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation. J Int Soc Sports Nutr. 2014;11:20. PubMed