Health and Fitness Calculators
12 tools, free and without ads.
A small set, and deliberately so. Health numbers are easy to generate and hard to interpret, and a tool that hands you a figure without saying what it can and cannot tell you is doing you no favours.
What is here computes from formulas that are published and checkable, on your device, with nothing recorded. What is not here is anything that would need to be a medical device to be honest.
Every tool in Health
Log your period and symptoms privately, and see your average cycle, next predicted period and estimated fertile window.
HIIT and Tabata timer: set work, rest and rounds, and follow the countdown with a beep at every change.
Focus in 25-minute blocks with short breaks and a long one every fourth session, all adjustable, with today’s focused time counted.
Calculate your Body Mass Index from height and weight. Metric and imperial.
Estimate calories burned during exercise by activity, duration, and body weight.
Log lifts set by set, see personal records by estimated one-rep max, and chart your progress per exercise — kg or lb.
Wilks, Wilks-2, DOTS and IPF GL points side by side from one total and bodyweight — with IPF GL for classic or equipped, three-lift or bench only.
Your estimated one-rep max by Epley and Brzycki side by side, with a percentage-of-1RM table and rep maxes from 1 to 12.
Stopwatch with lap tracking and countdown timer with audible alarm.
Log the water you drink in ml, fluid ounces or cups, against a daily goal, with the last seven days charted. Stored only in your browser.
Tick off daily habits, see the last seven days at a glance, and keep current and best streaks. Stored only in your browser.
Breathe along with a growing and shrinking circle — box breathing, 4-7-8 or your own timings, with a bell.
What these numbers can and cannot tell you
BMI — a ratio of weight to height, and that is the whole of it. It was designed to describe populations, not individuals, and it cannot distinguish muscle from fat or account for build. It is a rough screening figure and a poor verdict on any one person.
Calorie estimates — these come from average energy costs per activity and body weight. Real expenditure varies with fitness, technique, terrain and temperature, so the number is a reasonable order of magnitude and a bad basis for precise arithmetic against food intake.
The stopwatch and timer — makes no claims at all, which is why it is the most dependable tool in this category. Intervals, rest periods, anything you need counted.
None of these is a diagnosis or a substitute for advice from someone who can actually examine you. Use them to notice a trend and to ask a better question, not to answer one.
Related categories
- Cooking and Kitchen Tools — Meal planning and recipe scaling, the intake side of the same picture.
- Free Online Calculators — Pace, sleep and growth percentiles — body-adjacent maths filed with the general set.
- Astronomy and Outdoor Tools — A compass and spirit level, for when the exercise happens outdoors.