Evidence-aware · beginner-first · no miracle claims
Fitness calculators: BMI, water and protein in ten seconds
In one line: Three honest calculators that run in your browser - nothing is uploaded anywhere - plus the honest limits of each number.
Three numbers do most of the useful work in a beginner's fitness plan: roughly where your weight sits for your height, roughly how much water to drink, and roughly how much protein to eat. Enter them below - the calculators run entirely in your browser, and nothing is sent or stored anywhere. The numbers are general guidance, not medical advice.
1. BMI - where your weight sits
Height in centimetres, weight in kilograms. BMI is a rough population screen, not a verdict on any individual - muscular people read "overweight" on it all the time.
Your BMI appears here.
2. Daily water target
A common guide is about 30-35 ml of fluid per kilogram of body weight, more in heat or training. Food covers a share of it (the full picture).
Your target appears here.
3. Daily protein target
Common guidance for active people sits around 1.2-2.0 g per kilogram. This shows the range (the honest protein page).
Your range appears here.
What to do with the numbers
The BMI band is a starting marker, not a goal - how you feel, move and sleep carry more truth (the sleep page and starting from zero outrank any calculator). Use the water and protein targets as daily rails, and let the training side come from the exercise library and the programmes. If a number worries you, a professional reads it better than any website.
The plate loader
Barbells only move in jumps: the bar itself, then pairs of plates. Tell this tool what you want on the bar and it does the maths - which plates, which side, how close you can get to the number.
Sources
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Related on this desk.
General information, not medical advice. If you have a health condition, have been inactive for a long time, or something hurts sharply, talk to a qualified health professional first.