Health calculator

Macro Calculator with Body Fat % - Daily Protein, Carbs & Fat Targets

Free macro calculator with optional body fat percentage input for precise TDEE and macronutrient targets. Uses Mifflin-St Jeor or Katch-McArdle formula based on your data. Get daily protein, carbs, and fat grams for weight loss, maintenance, or muscle gain.

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years
inches

5'9" = 69 inches

lbs
%

Optional, enables the more precise Katch-McArdle formula

Daily Calories

–

Target intake

Protein

–

grams per day

Carbs

–

grams per day

Fat

–

grams per day

Using Mifflin-St Jeor formula

Don't know your body fat %? Use our body fat calculator to estimate it first.

How CalcMesh calculates macronutrients

We split your daily calories into protein, carbohydrate and fat, using the established energy densities of 4 calories per gram of protein, 4 per gram of carbohydrate and 9 per gram of fat. Ratios follow your goal, within the ranges the Dietary Guidelines for Americans recommend.

We convert calories to grams of each macro from your target and split; the ratio presets we use are documented in our methodology.

Macronutrient Guide

What Are Macros?

Macronutrients are the three nutrients your body needs in large amounts: protein (4 cal/g), carbohydrates (4 cal/g), and fat (9 cal/g). Each plays a distinct role in your body, and the right balance depends on your goals.

How This Calculator Works

This macro calculator estimates your Total Daily Energy Expenditure (TDEE) - how many calories you burn per day, then divides those calories into protein, carbs, and fat based on your goal.

The calculator supports two BMR formulas:

  • Mifflin-St Jeor (default): Uses height, weight, age, and gender. Accurate for most people with average body composition.
  • Katch-McArdle (when you enter body fat %): Uses lean body mass, making it more accurate for muscular or obese individuals. BMR = 370 + (21.6 × lean mass in kg).

If you know your body fat percentage, enter it above to switch to the Katch-McArdle formula. Don't know your body fat? Use our body fat calculator to estimate it.

Macro Splits by Goal

Goal Protein Carbs Fat
Weight Loss40%30%30%
Maintenance30%40%30%
Muscle Gain30%45%25%

Why Protein Matters Most

Protein is the most important macro for body composition. It preserves muscle during weight loss, builds muscle during a surplus, and has the highest thermic effect, 20-30% of protein calories are burned during digestion alone. That means eating 100 calories of protein nets you only 70-80 usable calories, making it harder to overeat. Prioritize hitting your protein target above all else.

Why Body Fat Percentage Matters

Two people who weigh 200 lbs can have very different caloric needs. Someone at 15% body fat has significantly more lean mass (and a higher metabolism) than someone at 35% body fat. By entering your body fat percentage, this calculator uses lean body mass to give you a more precise BMR, and therefore more accurate macro targets.

Adjusting Over Time

  • Track weight weekly (same conditions) for 2-3 weeks before adjusting.
  • Not losing weight? Reduce calories by 10% (mostly from carbs or fat).
  • Not gaining? Add 200 calories (mostly from carbs).
  • Feeling fatigued? You may need more carbs, especially around workouts.
  • Losing strength? Increase protein to 1g per pound of body weight.

Related Data

Look up nutrition facts, macros, and ingredients for 2M+ foods at USDA FoodData Central. Check supplement and vitamin data at NIH ODS.

Disclaimer: This calculator provides estimates for informational purposes only. Individual needs vary based on genetics, medical conditions, and other factors. Consult a registered dietitian for personalized nutrition advice.

After you get your split

What to do with the numbers

  • Hit the protein gram target first, before worrying about exact carb/fat precision - the thermic-effect math above shows protein is the macro that actually shapes body composition.
  • If you know your body fat %, enter it and re-run with Katch-McArdle instead of the default formula - two people at the same weight but different body fat get meaningfully different accurate targets.
  • Track weight weekly under the same conditions for 2-3 weeks before adjusting anything - the adjusting-over-time list above gives the exact tweak (10% calorie cut, +200 cal, more protein) for each stall pattern.
  • Re-run the calculator when your goal changes (cutting to maintenance to a gain phase), the protein/carb/fat percentages shift meaningfully by goal per the split table above.

Methodology & Assumptions

This ratio tool applies exact proportion identities to your operands. Percent change, share-of-total, and split modes differ only in labelling; the arithmetic path is deterministic.

How this ratio node runs

Percentage and ratio tools apply exact proportion identities. Change, of-a-number, and split modes share the same arithmetic family with different labelled inputs. Published domain formulas govern the identities; when an agency updates rates or thresholds we refresh defaults and the page lastmod.

Frequently Asked Questions

How much protein do I need per day?
A good starting point is 0.7-1g of protein per pound of body weight for active individuals. Endurance athletes may need 0.5-0.65g/lb, while those trying to build muscle benefit from 0.8-1.2g/lb. Sedentary adults can maintain health with as little as 0.36g/lb.
How does body fat percentage affect my macros?
Body fat percentage lets the calculator use the Katch-McArdle formula, which estimates your BMR from lean body mass instead of total weight. This is more accurate for people with high muscle mass or high body fat, since two people at the same weight can have very different caloric needs depending on body composition. If you know your body fat %, enter it for a more precise result.
Should I track macros or just calories?
Tracking macros gives more control over body composition and energy levels. Someone eating 2,000 calories of mostly carbs will have very different results than someone eating 2,000 calories with balanced macros. If you have specific fitness goals, tracking macros is worth the effort.
What are good sources of each macro?
Protein: chicken, fish, eggs, Greek yogurt, legumes, tofu. Carbs: oats, rice, sweet potatoes, fruits, vegetables, whole grains. Fats: avocado, nuts, olive oil, salmon, eggs, dark chocolate. Aim for mostly whole, minimally processed foods.
Do I need to hit my macros exactly every day?
No. Think of macros as weekly averages rather than daily targets. Being within 5-10g of each macro is close enough. Consistency over weeks matters more than precision on any single day. Focus on hitting your protein target first, as it has the most impact on body composition.
What is a good macro ratio for weight loss?
A 40% protein, 30% carbs, 30% fat split works well for most people cutting weight. The higher protein helps preserve muscle while in a calorie deficit. This calculator automatically adjusts macro ratios based on your selected goal, lose weight, maintain, or gain muscle.

This page identifies the inputs, method, and limitations behind its estimates. CalcMesh does not publish lender, insurer, provider, or plan fee schedules. Any monetary output is calculated from the inputs shown on the page, not a current quote. Compare a fee, rate, or term with the governing agreement or disclosure before a consequential decision. Calculator outputs are not professional advice. Ratio results here follow the proportion identity for your operands—no hidden benchmark percentage. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.

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Inputs, defaults, and authoritative sources
Input Default Source / authority
All inputs Domain-typical defaults Editorial methodology, CalcMesh 2026