What is a macro calculator?

A macro calculator estimates your daily calorie needs and how many grams of protein, carbohydrates, and fats you should eat based on your body data, activity level, and goals. It helps support weight loss, muscle gain, or weight maintenance through balanced nutrition planning.

How accurate is the DrinkDigits Macro Calculator?

The DrinkDigits Macro Calculator uses validated formulas such as the Mifflin-St Jeor equation and standard activity multipliers. The results provide reliable estimates for general nutrition planning and should be fine-tuned based on real-world progress and consistency.

Can I use this macro calculator for weight loss?

Yes. The calculator helps estimate a daily calorie target that supports gradual, sustainable fat loss while maintaining sufficient protein intake to preserve lean mass.

Can this macro calculator help with muscle gain or maintenance?

Yes. By adjusting calorie intake and protein targets, the calculator supports muscle growth, strength training goals, and long-term weight maintenance.

How often should I recalculate my macros?

Most people should recalculate their macros every 2 to 4 weeks, especially if body weight, activity level, or training intensity changes.

Does this macro calculator work for different diets?

Yes. The macro targets can be applied to a wide range of eating styles, including balanced diets, high-protein plans, lower-carb approaches, and plant-based diets.

What should I do after calculating my macros?

Use your macro targets to plan meals, track intake, and monitor progress. Adjust slightly over time based on energy levels, hunger, performance, and results.

Free nutrition tool

Your daily macros, dialed in.

Calories, protein, carbs, and fat targets calculated from your real body data. Under a minute, no signup, no upsell.

Start calculating

Mifflin-St Jeor formulaUSDA macro ratiosNo signup

Live previewSample

Daily target

2,358kcal

Protein177g (30%)

Fat79g (30%)

Carbs236g (40%)

Body composition

23.7

BMI

1,715

BMR

2,358

TDEE

Verified math

Basic information

Your body data drives the BMR calculation.

Gender

Average uses the midpoint of male and female formulas for non-binary users.

Units

Height

Weight (lbs)

Age (years)

Activity & goal

Pick the option that matches your real week, not your ideal one.

Activity level

Primary goal

Approach

Diet preference

Your results

Fill in your body data, activity, goal, and approach. Results show here.

Method

How the math works.

Three numbers drive everything: BMR, TDEE, and your calorie adjustment.

Step

BMR (Mifflin-St Jeor)

Calories your body burns at rest. Validated equation for healthy adults.

Men: 10×kg + 6.25×cm - 5×age + 5
Women: 10×kg + 6.25×cm - 5×age - 161

Step

TDEE

BMR multiplied by your activity level. Sedentary 1.2 up to Extra active 1.9.

TDEE = BMR × activity multiplier

Step

Target calories

TDEE plus or minus 200 to 750 cal based on your goal and approach. Floored at 110% of BMR for safety.

Target = TDEE ± adjustment

Reference

Activity multipliers

Level	Description	×
Sedentary Little or no exercise, desk job	Little or no exercise, desk job	1.2
Lightly active Light exercise 1-3 days per week	Light exercise 1-3 days per week	1.375
Moderately active Moderate exercise 3-5 days per week	Moderate exercise 3-5 days per week	1.55
Very active Hard exercise 6-7 days per week	Hard exercise 6-7 days per week	1.725
Extra active Very hard exercise plus physical job	Very hard exercise plus physical job	1.9

Reference

Macro split by diet

Diet	Protein	Fat	Carbs
Standard	30%	30%	40%
High Protein	35%	25%	40%
Low Carb	30%	40%	30%
Ketogenic	20%	75%	5%
Plant-based	15%	30%	55%
Mediterranean	20%	35%	45%

Protein = 4 kcal/g · Carbs = 4 kcal/g · Fat = 9 kcal/g

Back to calculator

Sources & reading

Where the numbers come from.

Methodology

Data sources

Calculations use the Mifflin-St Jeor equation for BMR, standard physical activity multipliers, and macronutrient ratios consistent with the USDA Dietary Guidelines. Cutting, muscle-building, and athletic-performance goals apply a 1.6 g/kg protein floor. Calories are floored at 110% of BMR for safety. Water targets use 30 ml/kg/day, fiber targets use 14 g per 1000 kcal (USDA).

01
Mifflin-St Jeor Equation
Am J Clin Nutr, 1990 (peer-reviewed BMR formula)
02
USDA Dietary Guidelines for Americans
2020-2025 macronutrient intake guidance
03
NIH ODS: Protein Fact Sheet
Evidence-based daily protein recommendations
04
ISSN Position Stand on Protein and Exercise
Peer-reviewed protein timing and dosing

Related guides

Long-form articles that go deeper on the math, the protein science, and the food pairings behind your numbers.

Editorial

Reviewed by the DrinkDigits Editorial Team

Updated May 14, 2026Verified against peer-reviewed research and brand nutrition data

Support

Frequently asked questions.

Short answers to the questions we hear most about this calculator.

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Calories + activity

TDEE Calculator

Total daily energy expenditure. Get the calorie number that feeds straight into your macro split.

Open TDEE Calculator