Age calculator
Work out an exact age from a birth date: years, months and days, the Chinese nominal age, total months and days, the Chinese zodiac and western star sign, plus a countdown to the next birthday and the weekday it falls on.
Runs in your browserEvery computation happens in your browser — your data never leaves this device.
Dates
A full calendar year is required for each year of age, and the remainder is split into months and days (month-end overflow is clamped). The Chinese nominal age is today’s year minus the birth year plus one, approximated by calendar years without a lunar conversion, and the zodiac is approximated the same way.
Age
Fill in the date of birth and “Today” to see the breakdown.
What this tool does
- Fill in a form or check eligibility: the exact age in years, months and days beats subtracting two years, and total months and days come along for free.
- Get the Chinese nominal age, zodiac and star sign in one place instead of digging through a calendar.
- Set up a birthday reminder: the next birthday, its weekday and the countdown in days are all in the result.
- Verify an anniversary: total days, weeks and hours are ready to use in copy or statistics.
Example
Input
Date of birth 2000-01-01, today 2026-10-10
Output
Age 26 years 9 months 9 days; Chinese nominal age 27; total months 321; total days 9779; total weeks 1397; total hours 234696; zodiac Dragon; star sign Capricorn; next birthday 2027-01-01 (Friday); countdown 83 days; age on that day 27
The nominal age is approximated by calendar years (today’s year minus the birth year plus one) with no lunar conversion, and the star sign follows the calendar date with boundary days belonging to the new sign.
Frequently asked questions
How is the Chinese nominal age calculated?
It counts a newborn as one year old and adds a year at each lunar new year. This tool skips the lunar conversion and approximates it as today’s year minus the birth year plus one, so it can be one year off around the Spring Festival — pair it with a lunar calendar tool when precision matters.
How does the exact age differ from subtracting years?
Each year of age needs a full calendar year: someone born on 2000-12-31 is only 25 on 2026-01-01, not 26. The remainder is split into months and days with month-end clamping, so a 31 January birth clamps to the end of February.
What about a 29 February birthday?
With month-end clamping the birthday falls on 28 February in a non-leap year, so someone born on 2024-02-29 turns one on 2025-02-28 and the “next birthday” row shows 2025-02-28. The result flags that the birthday was adjusted.
How are the zodiac and star sign boundaries defined?
Star signs follow the calendar date with the boundary day belonging to the new sign — 21 March is Aries and 22 December is Capricorn. The Chinese zodiac follows the lunar year but is approximated by the calendar year here: 2024 is the year of the Dragon, 2025 the Snake and 2026 the Horse, so people born around the Spring Festival may differ by one animal.
Why do I have to enter “Today” myself?
The tool never reads the system clock, so the same link and the same input always produce the same result and can be reproduced later. Press “Use today” to fill in your browser’s current date, and you can still edit it afterwards.
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