Hi, I'm Vinicius. I'm not a doctor or a nutritionist — just someone who has trained for years and likes to keep track of his own numbers.
Why I built this site
I've been lifting since I was 16, and I always missed a simple support tool with everything in one place: 1RM, macros, calorie burn, training zones. I started by gathering the calculators I used myself, then opened them up for people who, like me, want a quick answer without a paid app or a spreadsheet. The idea is to combine usefulness with clarity — showing the formula, not just the number.
I do it honestly: I'm not a health professional and the tools are educational estimates, not a diagnosis (the process is in How we calculate). For decisions about your health, always see a professional.
Talk to me
Found an error, want a calculator that doesn't exist yet, or have a way to make a tool clearer? Email me at contact@calculatorsfit.com or reach out on LinkedIn. Your feedback is the main way these calculators get better.
How every calculator is checked
Writing a formula and trusting it is not enough. Every calculation published here goes through three checks before it goes live, and that is what lets me stand behind a number without being a specialist myself:
- The formula is re-implemented from scratch, straight from the published equation or reference table, by a different route from the code that runs on the page. If the two results disagree, the calculator does not ship. Checking code against itself proves nothing, so the second calculation never starts from the first.
- Every number that appears in the text comes out of the calculator itself, never typed by hand. A worked example is a measured example: when a page says an adult of 1.75 m and 70 kg has a BMI of 22.9, that figure came off the tool on screen.
- Constants and reference tables carry an explicit reference year, in the code and on the page. When a health authority revises a classification, a cut-off point or a growth chart, the change is made by reading the official source — not by copying another website.
Where the numbers come from
None of the equations here are invented. BMI and its ranges follow the World Health Organization; the charts for children and teenagers follow the CDC; energy expenditure and training prescription follow the American College of Sports Medicine and the Mifflin-St Jeor equation; body fat uses the U.S. Navy method and validated skinfold equations. Each tool names its own source on its own page, and How we calculate lists them together.
What this site is not
Nothing here is a diagnosis or a medical prescription. A calculator result does not replace a consultation, a physical examination or a laboratory test, and it cannot see your history, your medication or your symptoms. That matters most in the tools that touch pregnancy, blood pressure, cholesterol, blood glucose and kidney function: those results are context for a conversation with a doctor, never a substitute for one. If a number here worries you — or if you feel unwell and a calculator tells you everything is fine — talk to a health professional. I am not a physician, a dietitian or a nurse, and I do not pretend to be one.
I also never see what you type. The maths runs inside your browser: the height, weight, age and readings you enter are not sent to any server and are not stored by me.
Found an error? Tell me
A wrong result is the kind of problem I want to hear about the same day. Write to contact@calculatorsfit.com or use the contact page, and give me three things: which calculator, which values you entered, and what result you expected. With those three I can reproduce the case and correct it. A fix always jumps the queue ahead of a new feature.