Basal Metabolic Rate Calculator J4NBasicCalc

DISCLAIMER: This project is something basic and example, many may be inspired, others, will not like much for the simple reason that, the macro calculation sometimes, is just that, pure calculation and the reality facing an athlete is beyond, for example stress, lots of muscle mass, nutrient absorption capacity, who does not like to eat, little appetite many variables. It is well known that high level athletes do not use any formulas, but they make their diets by means of the experience acquired during years and years of pure, hard and staunch training, plus observation of their own body, watching how it reacts, and from there, they add or subtract food.

J4NBasicCalc πŸ‹πŸΌβ€β™‚οΈ

It is a basic application to calculate the basal metabolic rate using MifflinSt/Jeor and Katch McArdle formulas, plus configurable random diets (add, remove foods, split foods to recalculate daily calories) in the 3 stages, definition, maintenance, volume. pdf report generation coming soon.

It has a module for approximate calculation of body fat.

The nutrition formulas all calculate the TMB/BMR by its acronym:

  • Basal Metabolic Rate

Depending on the nutritionist they will have different equations, for example:

Nutritionists Formulas

Katch McArdle

370 + (21.6 x Lean Body Mass (kg) )

Mifflins/St Jeor **Men**

(10 * weight (kg)) + (6.25 * height (cm)) - ( 5 * age) + 5;

Mifflins/St Jeor **Women**

(10 * weight (kg)) + (6.25 * height (cm)) - ( 5 * age) - 161;

Then that is multiplied by the physical activity factor which can range from 1.2 to 1.9.

Physical activity factor Range







Very Active




The following two images show the corresponding formulas for the calculation of the MAINTENANCE calories

Usage for BMR basal metabolic rate

- View of Mifflins / St Jeor


- View of Katch McArdle


Motivation for doing all this?

In this application the athlete is saved that tedious calculation of macros and percentages in an easy, simple and visual way with a few clicks, just the fatigue we suffer, muscle stress, mental, central nervous system, sympathetic and parasympathetic, and stop counting, which often causes that many times we can not even sit for different types of discomfort, one of them is that, extreme fatigue.

By making it possible to easily add or subtract calories to those maintenance calories calculated by both nutritionists, the next tab βš™Configure Macros, has the objective of setting these values to find the Macro-Nutrients.

Here you should enter the percentage values for each macronutrient, in 2 well known steps for example:

  • Low carbs

    • 45% proteins

    • 30% carbohydrates

    • 25% fats

  • High-carbs

    • 30% proteins

    • 65% carbohydrates

    • 5% fats

The number of times to eat should also be established, minimum recommended 3, and finally add or subtract calories to definition or volume stages.

View of βš™ Configurar Macros

This view is based on macronutrient calculations for both mifflins and katch.


General dietary view


The above image summarizes, that the past stages are mandatory for this one, to obtain tables with the 3 essential and random macronutrients for an athlete, for a minimal diet, etc, you can also include simple carbohydrates, legumes, and vegetables.

In future versions it will be possible to export to different formats such as .pdf, maybe there is the possibility of .xsls, .docx, etc.

colors based on πŸ‡»πŸ‡ͺ

β–ͺ View of Body-Fat approximate


This module is used for the calculation of 3 things that are:

  • (Body-Fat)

  • Lean body mass (Lbm)

  • Fat mass (Fat-Mass)

Here the Navy Seal formula is used to obtain an approximate fat % without a plicometer, and some other more complex and expensive techniques.

Gender Formula


495 / (1.0324 - .19077 * log10( WAIST(cm) - NECK (cm)) + .15456 * log10(HEIGHT(cm)) ) - 450


495 / (1.29579 - .35004 * log10( WAIST(cm) + WAIST (cm)) - NECK (cm)) + .22100 * log10(HEIGHT(cm)) ) - 450

Formulas for Fat Mass and Clean Mass (Lbm), thanks to the previously obtained bodyfat.

Type Formula

(Fat Mass)

(Body-Fat/100) * weight (kg)

Lean body mass (Lbm)

Weight (kg) - (Fat mass)

  • Username: user

  • Password: password

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