Birthday
Birthday Countdown Calculator
Days until your next birthday, the age you will turn and what day it falls on.
days = next birthday − today
Also called days until my birthday · birthday counter
Date & Time · 7 calculators
Birthday Calculators
Countdown to your next birthday, exact age, age in days, hours and minutes, the day you were born, half birthdays and zodiac signs.
Birthday
Age Calculator
Exact age in years, months and days from a date of birth, with the next birthday countdown.
Count whole years, then months, then rema…
Also called how old am i · date of birth calculator
Birthday
Age in Days Calculator
Your age in days, hours, minutes and heartbeats, with the milestone days coming up.
days = reference date − date of birth
Also called how many days old am i · days alive calculator
Birthday
Day of the Week Calculator
What day of the week any date falls on, past or future, with the week number.
Derived from the proleptic Gregorian cale…
Also called what day was i born · day of week for date
Birthday
Half Birthday Calculator
The date exactly six months from your birthday, and how far away it is.
half birthday = birthday + 6 months
Also called half birthday date · six months from birthday
Birthday
Zodiac Sign Calculator
Western zodiac sign and Chinese zodiac animal for a date of birth.
Determined by the date ranges of the trop…
Also called star sign calculator · what is my zodiac sign
Birthday
Age Difference Calculator
Age gap between two people in years, months and days, and how it compares proportionally.
difference = younger date of birth − olde…
Also called age gap calculator · difference in age
Key birthday formulas
| Birthday Countdown | days = next birthday − today |
|---|---|
| Age | Count whole years, then months, then remaining days |
| Age in Days | days = reference date − date of birth |
| Day of the Week | Derived from the proleptic Gregorian calendar |
| Half Birthday | half birthday = birthday + 6 months |
| Zodiac Sign | Determined by the date ranges of the tropical zodiac |
| Age Difference | difference = younger date of birth − older date of birth |
Birthday questions
How is age calculated exactly?
By counting completed years since birth, then completed months, then leftover days — not by dividing total days by 365.