How it's calculated
Your exact age and the totals below it are calculated the same way a calendar app calculates the time between two dates: your birth date/time and this exact moment. "Years, months, and days" is your age the way people normally say it (calendar-exact, not just total days divided by 365); the total weeks, days, and (if you gave a birth time) hours are the same underlying span of time, just expressed as one single number instead of a mixed year/month/day figure.
Your Chinese zodiac animal comes from the twelve-animal cycle (Rat, Ox, Tiger, Rabbit, Dragon, Snake, Horse, Goat, Monkey, Rooster, Dog, Pig). The Chinese year doesn’t begin on January 1 but at Chinese New Year, which falls on a different day between late January and mid-February. This tool checks that exact date for your birth year, so someone born on February 9, 2024 is still a Rabbit, while someone born a day later is a Dragon.
Your Western zodiac sign (the one in newspaper horoscopes) and your Vedic (Indian) sun sign both come from where the Sun actually stood at your birth, calculated astronomically — not from a fixed table of dates. The Western (tropical) zodiac starts at the March equinox; the Vedic (sidereal) zodiac of Indian Jyotish astrology is tied to the stars and today runs about 24 days later, because of a slow wobble of the Earth’s axis called precession. That is why most people have two different signs.
On the day the Sun moves into a new sign, the answer depends on the exact time of birth, so if you were born on such a day, enter your birth time too. Both results are sun signs only — a full Vedic birth chart would also need your Moon sign, ascendant and planetary positions, none of which this tool calculates.
The percentage of an assumed lifespan compares the total days you've been alive to a fixed, illustrative assumption of an 80-year lifespan — a single round number, not a personalized life-expectancy estimate for you. If you're older than 80, this percentage will honestly show more than 100%, not a capped 100%.
Next birthday
The calculator also shows when your next birthday is, which weekday it falls on, how many days are left and which age you will turn. If you were born on 29 February, 28 February is used in years that are not leap years. If you enter the date in the Persian calendar, the birthday is worked out in that calendar.
Year of birth from age
If you know someone's age but not their year of birth — for a form, say — subtract the age from the current year. If they have not had their birthday yet this year, subtract one more: someone who is 36 and has not celebrated yet this year was born 37 calendar years ago. The second calculator on this page does it for you.
Worked example
As an illustration: someone born on Friday, June 15, 1990 at 14:30 turned exactly 36 years, 0 months and 0 days old on June 15, 2026. At 14:30 that day they had been alive for 13,149 days — 1,878 full weeks — or 315,576 hours. They are a Horse in the Chinese zodiac (Chinese New Year 1990 fell on January 27, well before June), a Gemini in the Western zodiac and — only just — a Gemini in the Vedic zodiac too: the Sun had entered sidereal Gemini less than a day before. On that birthday they had lived through 45.0% of an assumed 80-year lifespan. The calculator itself always measures up to this very moment, so the numbers you see for the same birth date are a little higher and keep growing every day — that’s expected, not a bug.
Frequently asked questions
Why does it say my birth date "doesn't exist"?
Because the year/month/day combination you entered isn't a real calendar date — for example, day 31 in a month that only has 30 days, or February 30. Double-check the day and month you entered.
Why does it say my birth date is "in the future"?
This tool measures the time between your birth date and right now, so a birth date later than today can't produce a meaningful age or elapsed time. Check that the year is correct — a common cause is typing a future year by mistake.
Is the Chinese zodiac animal always exactly right?
Yes. It uses the actual date of Chinese New Year in your birth year, not January 1 — so if you were born in January or early February, you may get the previous year’s animal, and that is correct. For example, February 9, 2024 was still the Year of the Rabbit; the Year of the Dragon began on February 10.
Is the Vedic (Indian) sun sign a full Vedic astrology chart?
No — it is your sun sign in the sidereal zodiac of Indian (Vedic, Jyotish) astrology, calculated from the Sun’s real position at your birth. A full Vedic birth chart is far more involved: it needs your exact birth time and place to work out your Moon sign (rashi), rising sign and planetary positions, none of which this simple tool attempts.
What time zone does this tool use for "now"?
Yours. The calculator compares the birth date and time you enter with the current time on your device, reading both as local time — so your age goes up at midnight where you are, and a birth time of 14:30 means 14:30 local time. If you were born in a different time zone, the hours total is off by the time difference. (Only the example shown before you type anything is calculated in US Eastern time.)
Why are my Western and Indian (Vedic) signs different?
Because the two zodiacs start from different points. The Western zodiac is tied to the seasons — Aries begins at the March equinox — while the Vedic zodiac is tied to the fixed stars. Over the centuries the equinox has drifted about 24 degrees against the stars, so the Vedic signs now begin about 24 days later than the Western ones, and for roughly four people in five the Vedic sign is the sign before their Western one.
How do I work out a year of birth from an age?
Subtract the age from the current year. If you are 36 in 2026 and have already had your birthday, you were born in 1990; if your birthday is still to come this year, you were born in 1989. An age alone only gives the year (or two possible years); the exact day needs the full date. The “Year of birth from age” calculator on this page does the sum for you.
How many days until my birthday?
Enter your date of birth above: “Next birthday” shows the weekday, the number of days left and the age you will turn. It counts from today’s date on your own device.