Methodology
Every result on this site is arithmetic on the numbers you enter, compared against percentile breakpoints taken from published population datasets. This page explains how that works, and links to the exact tables behind each tool.
Four working rules
Everything runs in your browser
No measurement you type is sent to a server. Close the tab and the numbers are gone. That also means no account, no tracking of your inputs and nothing to delete later.
Every formula is written down
Each assessment lists the equation it uses and the percentile table it compares against, on its own reference page. There is no proprietary score anywhere on this site.
Comparison, not diagnosis
A percentile tells you how common your value is among people of your age and sex. It is not a risk score, a prognosis or a finding about your health.
Published sources only
Breakpoints come from national survey data and peer-reviewed norm studies. Where a distribution is interpolated between published deciles, that is stated on the reference page.
How a percentile is produced
- 01
Your inputs go into the published equation for that measure — for example waist ÷ height, or the Mifflin-St Jeor energy equation.
- 02
The result is matched to the reference table for your sex and age band. Bands are ten years wide, because that is how the underlying norm studies report them.
- 03
Your value is placed between the published 10th, 25th, 50th, 75th and 90th percentile breakpoints by linear interpolation. Values beyond the outer breakpoints are shown at the edge rather than extrapolated.
- 04
The curve you see is a display device showing a typical population shape. The marker position is the real interpolated percentile.
What each tool uses
Formulas, tables and citations per measure. Every line links to its full reference page.
Waist-to-height ratio is close to sex-independent in adults, so one distribution is used for everyone aged 18 and over.
2 published sources · 1 table
Distributions are drawn from resting pulse measurements in large adult survey samples, split by sex.
2 published sources · 1 table
Scoring follows the original protocol: one point removed per hand, knee, forearm or side-of-leg support, half a point for a loss of balance, applied to both sitting down and standing up.
1 published source · 2 tables
Two published estimating equations are used. Resting-pulse method: VO2max ≈ 15.3 × (maximum HR ÷ resting HR), with maximum HR taken as 220 − age. Cooper method: VO2max ≈ (distance in metres − 504.9) ÷ 44.73.
3 published sources · 2 tables
Dominant-hand maximum grip in kilograms, by sex and ten-year age band.
2 published sources · 2 tables
Mifflin-St Jeor: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5 for males, − 161 for females. Total daily energy = BMR × activity factor.
2 published sources · 1 table
The weighted weekly average assumes five work nights and two free nights. Catch-up is free-night sleep minus work-night sleep.
2 published sources · 2 tables
Office blood pressure categories as published by the European Society of Cardiology and the European Society of Hypertension.
1 published source · 1 table
rMSSD distributions narrow steadily with age. Values here reflect overnight or supine short recordings.
2 published sources · 1 table
Norms are per test, sex and ten-year age band. Push-up standard: full range, body in a straight line. Plank: forearms, hips level. Squats: thighs to parallel, counted over 60 seconds.
3 published sources · 6 tables
Each answer carries a fixed weight in years. The offsets are summed and added to chronological age. Nothing is hidden and nothing is fitted to you individually.
3 published sources · 8 tables
Limitations we will not paper over
- Self-measurement is noisy. A tape measure held differently, a dynamometer of another brand or a pulse taken after coffee can move you a whole percentile band.
- Reference datasets skew towards European and North American adults. If your ancestry or country is not well represented in those samples, the comparison is looser.
- Estimating equations, especially for VO2max and energy expenditure, carry meaningful error per person even when they are accurate across a group.
- A percentile describes a population, not you. Being at the 20th percentile for any measure is not a finding about your health.
Scope
These tools present population comparison and general wellness information. They do not diagnose, treat, predict or prognose disease, and no result should be read as individualised medical risk. If something concerns you, take it to a clinician who can see the rest of your history.
Found an error in a formula, a breakpoint or a citation? Tell us and we will publish the correction.