Achieving Personal Potential

Body Optimisation Calculator

Through a comprehensive series of well-validated clinical health calculations, markers and indicators, this Body Optimisation Calculator, combined with a few body measurements, will assist in evaluating overall body composition, physical fitness and even potential disease risks, as well as providing suggestions for the daily intake of various diet, water and activity levels to suit current personal needs, and therefore assist with achieving personal body goals.

Key Functions

Body Mass Index (BMI) Calculation
Waist-to-Hip Ratio (WHR) Calculation
Ideal Body Weight (IBW) Calculation (Multiple Formulas: Robinson, Miller, Devine, Hamwi)
Body Fat Percentage (BFP) Calculation (Multiple Formulas: Dept of Defence, Covert Bailey, Heritage, YMCA, Modified YMCA)
Body Fat Percentage (BFP) Manual Entry (if obtained from medical DEXA Scan)
Total Fat Mass (TFM) Calculation
Fat Mass Index (FMI) Calculation
Lean Body Mass (LBM) Calculation
Fat Free Mass Index (FFMI) Calculation
Adjusted Fat Free Mass Index (Adjusted FFMI) Calculation
Basal Metabolic Rate (BMR) Calculation (Daily Energy Needs – Multiple Formulas: Mifflin-St Jeor, or Katch McArdle)
Minimum Protein Requirement Calculation
Weight Management Goal (for adjusting Daily Energy Intake)
Preferred Diet Selection (for Tailored Macronutrient Ratios: High Protein, Low Carb, High Carb, Low Fat)
Estimated Daily Water Requirements Calculation (based on Gender, Body Size, Environment and Exercise levels)
Save, Load & Print Functions

(See instructions below, for more information)


1. You must Login to your account to access the calculator.

2. Review each of the tabs in the ‘Entering Your Data‘ section below the calculator
(click on each tab, to ensure you understand how to correctly select, collect and enter all data).

A Tape Measure is required.

3. Review the further information sections that follow at the bttom of this page.
(to learn the science and implications behind each of the markers/calculations, and how to make appropriate interpretations of them, before drawing any conclusions and proceeding to work on any personal body and lifestyle goals).


Taking multiple up-to-date measurements will ensure the greatest accuracy.
You will be able to download and save your inputs & results for later uploading back into the app
(to make further adjustments over time).

Please Note:
The results offered by this calculator depend on numerous factors to be made fully relevant and applicable to you. The calculations may be useful for providing you and your health practitioner with some objective indicators of your personal health status and needs. However they should not be considered diagnostic, nor directly advisory. Please always consult your chosen healthcare practitioner for personalised advice before taking any relevant actions regarding your health.

Body Optimisation Calculator


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Entering Your Data


Select your preferred measurement units between either:

Standard International Metric Units (e.g. kg and cm)
US Imperial Units (e.g. lbs and inches)

You can change your units selection at any point, and all input values will be converted ‘on-the-fly’.
(this may be useful if you know some of your data in one set of units, and some in another)
(e.g. you know your weight in kg but know your height in inches).


Select biological sex.


Simply enter Age in years.

You can click on the
icon to switch to entering a specific birth date.
The age will then be calculated automatically.
(Tip: Click on the
icon to the right to use a date picker)

Note: Adding an actual date will allow the DOB to be saved in the data file
(to provide better patient identification for clinical records).


Enter your height

(measured without shoes, in a single measurement – correct to your chosen units).

If using US Units to enter height in Inches:
Remember that there are 12 inches in a foot (5 feet = 60 inches)
(If you are ‘5 foot 8 inches’, simply add 60 + 8)
(5’ 8” = 68 inches)


Enter your weight, correct to your chosen units.


Use high quality scales, designed for human body weight measurement, on a hard, flat and level surface (not carpet).
Ensure scales have been ‘zeroed’ and calibrated correctly before use.
Take weight measurements in the morning, without clothes, after going to the bathroom, and before eating or drinking.

Activity Level (Exercise)

Select the activity level that most typically applies at present (i.e. during MOST weeks over the past 6 months):

Nil You rarely make any effort to exercise or be active, and your general lifestyle is almost entirely sedentary (mostly seated), doing such things as working on a computer, reading, watching TV, driving a vehicle, etc.
Low You are on your feet for parts of the day (at least 2 hours) doing such things as cleaning, shopping, tradeswork, etc. and occasionally engage in light exercise (such as walking, golf, table tennis, etc.) on about 1-3 days of the week.
Moderate You are active during your day (at least 3 hours), and relatively frequently engage in moderate exercise (such as hiking, jogging, swimming, cycling, dancing, weight training, tennis, etc.) on about 3-5 days of the week.
High You are active (at least 4 hours per day) and regularly engage in hard continuous exercise (such as sprinting, rock climbing, basketball, football, soccer, etc.) on most, if not all, days of the week.
Very High You have a very physically demanding job (5 hours or more per day) doing such things as heavy digging, tree chopping, etc., and/or you athletically train heavily and extensively (once, if not twice) every single day (such as marathon training).


A Note on Activity Levels:
Regardless of your weight or diet goal, you should aim to be achieving at least a ‘Low’ level of activity before forming any diet or weight goals based on BMR calculations.

Movement is required for health, far beyond mere weight management – and exercising less to justify eating less is not a path to health, nor necessarily is exercising more, solely to compensate for overeating high-caloric, low nutrient, foods.

Both ‘Nil’ and ‘Very High’ Activity levels can both have negative consequences for health.

The optimum activity level and type for you is determined by age, capabilities and goals, etc.
(this calculator may therefore assist in forming more personalised guidelines).

Climate / Environment

Select the typical ambient environment / climate that you spend most of your day exposed to:
(during the current season – or what is experienced for the majority of any given year in your region).

Extreme Cold: (avg. below 10ºC) Frost or ice are common -or- is often very cold, with clear skies (dry cold).
Normally Cool: (avg. 10 – 20ºC) The majority of the time multiple layered / warm clothing is most comfortable, and sweating is rare.
Normally Warm: (avg. 20 – 30ºC) The majority of the time, short and loose clothing are most comfortable, and occasional/light sweating is common.
Extreme Heat: (avg. over 30ºC) Heat waves, tropical or desert regions, and other circumstances where extreme heat with dryness, or humidity with frequent sweating, are common.


The appropriate selection will assist in estimating your likely daily hydration needs (in tandem with your body weight and level of activity).

Accurate Tape Measurements

Enter precise tape measurements, correct to your chosen units, for the circumference of each key body region.

Note Regarding Correct ‘Locations’:
The body location of ‘circumference measurements’ used for healthcare purposes may differ from those used for clothing fitting purposes. It is important that you take note to collect correct measurements precisely according to the following guidelines.

Care should be taken to ensure that your measurements are taken accurately.
This will help to ensure that this calculator can make the most accurate calculation as possible (esp. for Body Fat Percentage).

The best time to make body measurements (for maximum accuracy) is in the morning after a full night’s rest.
Note: Measurements should NOT be done immediately after exercise, (due to the shift in body fluid to the skin).
The phase of the menstrual cycle, as well as any food sensitivity reactions, may each also have an effect on some circumference measurements (due to changes in water retention).
If self-measuring, use a mirror to ensure the tape measure is horizontal and not twisted.
Remove all layers of clothing to allow direct skin contact with the tape measure wherever possible.
All measurements should be taken in a relaxed state, (relaxed muscles, normal posture, and after exhalation.
Always measure the dominant arm and dominant leg (whether right or left handed/footed).
Do not pull the tape measure too tightly (so as to depress the skin significantly).
Do not use a measuring tape that is old or stretched out.
Most measurements should be made at the point of greatest girth for each body part (unless otherwise specified).
The formulas require measurements to be within an accuracy of 0.5 cm (1/4 of an inch).
To achieve optimum accuracy, perform each measurement 2-3 times
(and take an average, after confirming the correct locations are being measured)

How to Measure

Body Tape Measurements Male & Female


Hips: With relaxed muscles, feet shoulder-width apart, and the least amount of obstructing clothing appropriate for the situation (thin/form fitting clothing may be acceptable, but naked/underwear is ideal for precise measurement).

Measure level horizontally at the widest point of greatest girth below the hip bones (including the furthest protrusion of the buttocks – this is usually closer to the femoral head (the ‘hip socket’), rather than the iliac crest (the ‘hip bones’ themselves).

Note: This is not required for most calculations of male body fat percentage.

Waist: Women:
At the end of a natural (non-forced) exhalation, measure level horizontally at the location of the narrowest abdominal width (usually at the softest point between the ribs and hip bones, just above the navel).

At the end of a natural (non-forced) exhalation, measure level horizontally at precisely the level of the navel.
This is NOT necessarily the level of narrowest abdomen width for men.

* If unsure, measure a second and third time to ensure the lowest correct value.

Note: There is a precise difference between waist and hip locations on the body (esp. between men and women), despite how these terms may be used casually in your part of the world.
Neck: Looking straight ahead, with shoulders down and relaxed, wrap tape at an angle sloping slightly downward to the front (to rest just below the Larynx/Adam’s Apple).

Note: Include neck only (i.e. minimise the inclusion of any shoulder muscles)

Forearm: Measure the forearm at the point with the largest muscular girth below the elbow.
Wrist: Measure at the same location as a wrist watch, avoiding the ulnar styloid process.
(i.e. select either side of the ‘wrist bone lump’)
Thigh: Women-Only:
Standing relaxed with legs slightly apart, measure the thigh at the point of largest girth.
(usually just below the buttocks)
Calf: Women-Only:
Seated if measuring self, otherwise standing if receiving assistance, measure the calf at the point with the largest muscular girth below the knee.

Understanding Your Results

Why Use So Many Indicators?
It is better to consult numerous indicators in order to get a bigger picture of true body status.

Because each indicator has it’s own weakness (things that it may confuse or miss about the health of the body), carrying out many calculations helps to get a more overall view of body health and its numerous comprising factors (any imbalances are far more likely to be detected the more analyses you perform).

Additionally, everyone has their own different needs and goals.

These various assessments will help you anchor goals to what is relevant and appropriate to your specific needs and targets for optimum health.

Why Multiple Formulas for The Same Indicator?
Because they too each have their own weaknesses (e.g. some formulas lend themselves to men, some to women, some lose relevance when entering a really tall or short height), so many of these failings can be overcome by first getting an array of results (so no one single result is being relied upon), and doing some research on each formula, this will allow more perspective and may then assist selection of the most appropriate formula for the individual, goals and situation – OR – an averaging of all the formulas can help eliminate some of the the limitations inherent to any one formula and provide a suitably sound overall guideline to base ongoing targets against)

Rounding Result Values
Even though many results display to 2 decimal places, this is not intended to imply that all results are specifically accurate to that degree (a variation of about 1-3% applies to most included calculations). These decimal places simply help ensure the broader accuracy of the entire calculator (as many subsequent results rely on numerous previous results in order to be calculated correctly).
So simply read an Ideal Body Weight value of ‘55.62 kg’ as 55 kg
or a water requirement of ‘2088.12 ml’ as 2L (after all it’s just a guide)

Limitations Of The Formulas
Remember that these equations fit populations not the individual. See more discussion and research on each of the selectable formula methods for more information that may best suit the individual being assessed. If in doubt, simply use ‘Average of ALL Formulas’ selection (it will remain surprisingly accurate for most situations, and in some cases is the MOST appropriate choice)


Body Mass Index

The Body Mass Index (BMI) is a simple standardised calculation of body proportions (represented in kg/m2, as if the body was a flat 2 dimensional shape) to determine how appropriate a body weight is, relative to height.

The BMI calculation is based on:
– Height
– Weight

BMI Indications Chart
(Click to enlarge)

The WHO recommends a BMI of 18.5-25 (for both Men and Women).


Waist-Hip Ratio

Your Waist-to-Hip Ratio (WHR) is an approximation of your body dimensions, and may reveal where certain imbalances have been statistically correlated with poor health outcomes or increased disease risk.

The WHR calculation is based on:
– Waist Circumference
– Hip Circumference

How to Measure?
What exactly is your ‘waist’ and what is your ‘hip’?
Take your measurements from the locations described in the ‘measurements’ tab of the Instructions section above.

Waist-Hip Ratio Indications Chart
(Click to enlarge)

Our health is not only affected by how much total body fat we accumulate, but also by where a significant portion of that fat is distributed on our body. People who carry most of their excess fat in their hips and buttocks have what is roughly described as a ‘PEAR’ body shape. While those who carry more fat around their abdomen have what is referred to as an ‘APPLE’ body shape .

Those of us with APPLE shaped bodies are generally considered to have an increased risk of experiencing the health problems associated with obesity, such as diabetes, coronary heart disease and high blood pressure.

While our general body shape is genetically determined, with the right diet and lifestyle practices, it is still possible to optimise your natural shape for your optimum health.

As long as excess weight can be minimised, having an apple or pear shaped body doesn’t necessarily dictate disease – it is simply one of those things to look out for when evaluating your overall health. Even pear shaped individuals should take particular care to keep their weight within normal limits, to avoid the health problems associated with excess body fat accumulation.

While the WHR can be useful in providing a guide (especially when used in combination with other guides like the BMI), it also remains only a guide.

Further indicators, such as Body Fat Percentage (BFP) and Fat Mass Index (FMI) may be required to get an appropriate perspective of fat distribution in the body.

‘Apple’ vs ‘Pear’ Body Shape


Body Fat Percentage

Having an indication of the actual percentage of body weight that is attributable to all fat on the body, is highly valuable for both clinical assessments and disease risks, and also for monitoring changes in body composition from diet and lifestyle change over time.

The Body Fat Percentage can be calculated relatively accurately from various body measurements alone.

The different formula methods available differ in terms of their level of refinement from the size and diversity of the population they were derived from. All the BFP formulas take male and female body shape and fat distribution differences into account.

Body Fat Percentage Indications Chart
(Click to enlarge)


Fat Mass Index

The Fat Mass Index (FMI) is a simple calculation, similar to the BMI, that estimates the appropriateness of the fat weight relative to height.

This ‘fat focussed’ version of the BMI, is therefore potentially far more appropriate for assessing metabolic disease risks, and unlike BMI will not penalise individuals with larger amounts of muscle by grouping them into ‘obese’ categories.

Fat Mass Index Indications Chart
(Click to enlarge)

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