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Free Calculators
Free Health and Metabolism Calculators
Pick a calculator. Each one runs in your browser and never asks for your email.
01
BMI Calculator
Scales your weight to your height and shows the standard adult categories, along with a clear account of what the number cannot tell you.
What it uses
Height, weight
02
BMR Calculator
Estimates the calories your body burns at complete rest using the Mifflin-St Jeor equation, plus estimated daily burn at five activity levels.
What it uses
Sex, age, height, weight, activity
03
TDEE Calculator
Estimates your total daily energy expenditure: resting burn plus movement plus the energy cost of digesting food.
What it uses
Sex, age, height, weight, activity
04
Calorie Calculator
Estimates your maintenance calories and a daily target based on the gap between your current weight and your goal weight, with a rough timeline.
What it uses
Sex, age, height, weight, goal weight, activity
05
Body Recomposition Calculator
Estimates the calories and protein for losing fat while building muscle, targeting maintenance rather than a deficit, with separate training-day and rest-day figures.
What it uses
Sex, age, height, weight, activity, body fat % (optional)
06
Protein Calculator
Estimates a daily protein range in grams for maintaining, losing fat, or building muscle, split per meal, with everyday food examples.
What it uses
Sex, age, height, weight, activity, goal, GLP-1 (optional)
07
Weight Loss Percentage Calculator
Shows the percentage of body weight lost between two weigh-ins, and what 5%, 10%, and 15% mean clinically.
What it uses
Starting weight, current weight
08
Macro Calculator
Turns a daily calorie target into grams of protein, carbohydrate, and fat for losing, maintaining, or gaining weight, with a per-meal split and a protein-first option.
What it uses
Sex, age, height, weight, activity, goal, macro split
09
FFMI Calculator
Works out fat-free mass, FFMI, and height-normalized FFMI from your height, weight, and body fat, with a tape-measure body fat estimate and a comparison between two measurements.
What it uses
Sex, age, height, weight, body fat % or tape measurements
10
Lean Body Mass Calculator
Estimates lean body mass from your sex, height, and weight with the Boer, James, and Hume formulas side by side, or directly from a body fat percentage.
What it uses
Sex, age, height, weight, body fat % (optional)
11
GLP-1 Weight Loss Calculator
Applies published clinical-trial averages for semaglutide and tirzepatide to your current weight, as a range of trial outcomes rather than a prediction. Compounded GLP-1 is not FDA-approved.
What it uses
Medication, sex, age, height, current weight
12
GLP-1 BMI Requirement Calculator
Calculates your BMI and shows it against the FDA-label criteria for the weight-management GLP-1 medications. A physician, not a calculator, decides whether treatment is appropriate.
What it uses
Height, weight, weight-related conditions
Your inputs stay in your browser. Nothing you type here is sent to us, saved to an account, stored, or emailed. Like any page on this site, we do record that the page was visited.
The short answer
These six calculators estimate different pieces of the same picture. BMI scales your weight to your height as a rough population screen. BMR estimates the calories your body burns at complete rest. TDEE adds movement and digestion on top of BMR to estimate your total daily burn. The calorie calculator takes that total and turns it into a maintenance figure and a daily target. The body recomposition calculator takes the same total the other way: it holds calories at or near maintenance and sets a protein target, because losing fat while keeping muscle is not a deficit problem. The GLP-1 calculator sits apart from that chain: it applies published clinical-trial averages to your current weight to show a range of trial outcomes, not a prediction of your own. Every one of them runs entirely in your browser, returns a result instantly, and never asks for your email.
How this works
How These Calculators Fit Together
Three of the four form a single chain. BMR is the floor of your energy use, the calories your body spends at complete rest. TDEE is that BMR multiplied by an activity factor, so it estimates everything you burn across a full day, movement and digestion included. The calorie calculator takes that total and adjusts it toward a goal, which is where a daily target comes from. BMI sits outside that chain. It is a separate screening measure built from height and weight alone, and it says nothing about your energy needs. The GLP-1 calculator sits outside the chain too. It does no energy arithmetic at all: it applies percentages published in two clinical trials to the weight you enter, and it deliberately shows nothing below the BMI range those trials enrolled.
What These Tools Do Not Do
Each of these is an estimate produced by a published equation, and it is worth being precise about what that leaves out.
- They do not diagnose. No number here identifies a condition or rules one out.
- They do not measure. The only real measurement of resting metabolism is indirect calorimetry, performed in a clinical setting. An equation predicts a value from your height, weight, age, and sex. It does not measure anything about you.
- They do not account for medications, thyroid function, pregnancy, or body composition. All four change what your body actually needs, and none of them are inputs to any equation on this site.
- They are not a treatment plan. A figure from a calculator is a starting point for a conversation with a clinician, not instructions for how to eat, train, or treat anything.
How Protocol MD Approaches This
Protocol MD is a physician-guided peptide therapy practice. Licensed physicians evaluate performance, longevity, and body composition, alongside recovery, sleep, energy, and cellular health. If you want the background first, here is what peptide therapy is and how it is used.
A calculator estimates energy needs. It cannot tell you whether any treatment is appropriate for you. Only a licensed physician can, after a full assessment.
Educational only. This tool does not diagnose, prevent, treat, or cure any condition, and it is not medical advice or a recommendation of any specific therapy.
Using this calculator does not create a physician-patient relationship with Protocol MD.
