Calculator

Daily water recommendation by weight, activity and weather, with a timed plan.

Split a bill with tip among friends in one click, instantly.

Reverse-engineer the best wake or bed time from 90-minute sleep cycles.

Solve the unknown ratio term, scale values and simplify fractions.

Estimate the due date, current gestational weeks and milestones from LMP.

Three modes in one click: part-of, percentage-of and change rate.

Instantly computes monthly payments, total interest and a full amortization schedule for both repayment methods.

Project the future value of a lump sum plus monthly contributions.

Compare simple and compound interest year by year instantly.

Enter credits and scores to compute per-course points and weighted GPA.

Turn distance, litres and price into L/100km, cost per kilometre and full-tank range.

Usage times editable tiered rates, billed progressively with a breakdown.

Add or subtract days, hours, minutes and seconds with multi-unit totals.

Days between two dates, and add/subtract days to find a new date.

An editable table of common currencies for converting any pair in both directions.

Estimate body fat percentage with the US Navy circumference method, with gender-specific formulas.

Instantly compute your body mass index from height and weight with colour-coded WHO bands.

Age Calculator is a completely free, instant-use online tool that helps you quickly and precisely obtain all kinds of age information from a birth date. Simply pick or enter a birth date and the tool instantly returns multiple results: exact age in years, months and days, total days lived since birth, the countdown to the next birthday, plus the matching Chinese zodiac sign and Western zodiac sign — everything you need at a glance. The tool strictly follows the Gregorian calendar and automatically handles leap years, short months, and year boundaries, so results stay accurate no matter when the birth date falls. It suits a wide range of scenarios: verifying your exact age for resumes, ID documents and school enrollment; parents tracking a baby's growth by checking month-age and key milestones; planning birthday surprises for friends and family by seeing how many days remain until the next birthday; HR and admissions staff verifying ages in bulk; or simply satisfying everyday curiosity about how many days you have lived in this world. The tool also supports one-click copy and result download for easy archiving and sharing, includes a built-in example date for instant demonstration, and offers a native date picker that works with keyboard input on desktop and the system calendar on mobile — zero learning curve. All calculations happen locally in your browser without any server round-trip, so your birth date and personal information are never uploaded and your privacy is fully protected. The interface is clean and lightweight, available in Simplified Chinese, Traditional Chinese and English, automatically follows the website language, theme color and corner-radius style, and stays visually consistent with the whole site. No registration, no installation — just open and use, fully responsive on desktop and mobile. Age Calculator is your practical everyday companion for date and age queries.