Eleven free health calculators that check your own numbers against published norms: fitness age, VO2 max percentile, grip strength, protein intake, body fat and more. No sign-up, nothing stored.

Catalyst Health Calculators is a free suite of eleven browser-based health and fitness calculators, built by Catalyst Performance, a longevity-focused personal training studio in the Singapore CBD. They all answer one question that is usually answered badly, vaguely, or not at all: is my own number normal for someone my age?

The suite covers fitness age, VO2 max percentile against the FRIEND reference registry, grip strength against the AWGS sarcopenia thresholds, waist-to-height ratio, the sitting-rising test, GLP-1 muscle loss, fat loss timelines, running pace prediction, heart rate training zones, daily protein intake, and body fat percentage by the Navy tape method.

The protein calculator is a fair example of the approach. It turns your body weight into a daily target in grams, and deliberately shows two numbers rather than one, because the honest answer depends on what you are asking your body to do. The first is a maintenance floor of 1.2 to 1.6 grams per kilogram, the range the research supports for preserving lean tissue in adults who are not training hard. The second is a training target of 1.6 to 2.2 grams per kilogram, which applies if you are lifting seriously, eating in a deficit, or both at once. Losing weight and keeping muscle are competing goals, and protein is the main lever that lets you have some of both.

Every calculator in the suite works the same way. Enter your numbers and it returns your result with the reasoning shown rather than hidden behind a result screen. There is no account to create, no email to hand over, and nothing is stored. The maths is deterministic and runs entirely in your browser against static reference tables, so each one loads instantly and behaves identically whether you are the first visitor of the day or the thousandth.

Every reference table and threshold traces back to a primary source, and those sources are listed on each page rather than summarised away. Where the evidence gives a range rather than a single figure, the tool shows the range. Where an estimate is an estimate, it says so plainly, and points out that the measured version is a different thing entirely. That last part matters more than it sounds: a calculator is a useful first look, not a substitute for testing, and any tool that pretends otherwise is selling something.

All eleven calculators are free to embed on any other website, with a copy-and-paste snippet and no permission required.