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Health & Lifestyle Tools — Free Online Calculators

Free calculators for BMI, age, habit tracking, and everyday health.

Simple, focused calculators for everyday personal stats. Use them to check a number you are curious about, confirm a form you are filling out, or build a small habit routine. Nothing you type is ever stored on a server.

All Lifestyle tools (3)

Age Calculator

Calculate exact age from birth date

BMI Calculator

Body Mass Index calculator

Habit Tracker

Track daily habits and goals

What you can do in this category

The BMI calculator accepts both metric and imperial units and returns your body mass index together with the standard health-category range. The age calculator computes an exact age in years, months, and days from a date of birth — useful for paperwork, trivia, and verifying ages on forms. The habit tracker gives you a lightweight way to mark off daily habits and watch streaks build up, stored locally in your browser so the data stays on your device.

How to interpret your results

BMI is a screening tool, not a diagnosis. A number in the "normal" range is a good sign; a number outside it is worth a conversation with a clinician, but not an emergency. Age in days is accurate to within a day depending on what time the calculation runs at midnight. Habit streaks are most useful as a short-term motivator — studies suggest that visible progress is one of the most reliable drivers of consistency in behavior change.

Related reading

For a detailed walk-through of the BMI formula, the mistakes people make when computing it, and when it is misleading, see our guide on how to calculate BMI correctly.