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What Day Was I Born
Find the weekday you were born on, see your birth month as a calendar, and see which weekday each of your next birthdays falls on.
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| Birthday | Age | Weekday |
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Hebrew and Islamic days begin at sunset, so a birth after sunset belongs to the next date in those calendars. The Hijri date follows the Umm al-Qura calendar and can differ by 1 or 2 days from local moon sighting. The Chinese zodiac animal changes at Chinese New Year, in late January or February.
A what day was I born calculator finds the day of the week of any date of birth. Enter the date, and the calculator counts the days from a date with a known weekday, divides by 7 and names the weekday you were born on, from Monday to Sunday.
The calculator gives 4 main benefits: an instant answer for any date since 1582, a calendar of your birth month, the weekdays of your next 8 birthdays and extras such as your zodiac sign, birthstone and Hebrew and Islamic dates. People use it out of curiosity, for birthday party planning, for family history and to check the "Monday's Child" rhyme. It has 4 parts: the date of birth field, an "I turned … today" option, the result with its calendar and the weekday wheel that shows the maths.
Lines from the traditional English rhyme "Monday's Child", which ends "the child that is born on the Sabbath day is bonny and blithe, and good and gay". Akan day names come from Ghana. Both are folklore, not prediction.
How to Use the What Day Was I Born Calculator
To use the what day was I born calculator, enter your date of birth and press Find my weekday. The process takes 3 steps, and a second option works from your age alone.
- Date of birth08/15/1990Enter your date of birth.
The field accepts any date from October 15, 1582.
- Find my weekday →Press Find my weekday.
The answer appears straight away, with no page reload.
- Born on a WednesdayLeo · PeridotRead the result.
Weekday, rhyme line, birth-month calendar, next 8 birthdays and 6 extras.
- I turned … today21Or use your age.
Turned 18 or 21 today? Enter the age and the calculator finds your birth weekday.
Dates follow your device's format: dd/mm/yyyy in the UK and Australia, mm/dd/yyyy in the United States. Nothing you enter leaves your browser.
How Is the Day of the Week You Were Born Calculated?
The day of the week you were born is calculated by counting the days between your date of birth and a date with a known weekday, then dividing by 7. The remainder says how many weekdays to step forward from the known one. AgeCountLab uses Saturday, 1 January 2000 as the anchor and the Gregorian calendar rules for leap years.
n = days from Saturday, 1 January 2000 to the date of birth remainder = n mod 7 (0 to 6; negative n wraps around) weekday = Saturday + remainder 20 July 1969 (Neil Armstrong walks on the Moon) n = −11,122 days remainder = 1 weekday = Saturday + 1 = Sunday
The weekday wheel
Start from a date whose weekday we know, count the days to your birth date, divide by 7 and keep the remainder. The pointer steps that many days around the week to land on your weekday.
Showing 15 August 1990. Enter your date of birth in the calculator to spin your own.
In code
// JavaScript in any web browser new Date(Date.UTC(1969, 6, 20)).getUTCDay() // 0 = Sunday =TEXT(A1, "dddd") ' Excel or Google Sheets
JavaScript counts months from 0, so July is 6. Excel and Google Sheets return the weekday name directly.
Why 7 works
Weekdays repeat every 7 days without a break, so 2 dates a multiple of 7 days apart always share a weekday. Leap years only change the day count; the calculator counts real calendar days, so every February 29 is included.
How to Calculate Your Birth Weekday Manually
To calculate your birth weekday manually, use the key value method: add 5 numbers, take away 1 for January or February of a leap year, and divide by 7. The remainder gives the weekday.
Month keys
Century keys
Remainder → weekday
Muhammad Ali, born 17 January 1942
1942 is not a leap year, so no correction applies. Dividing at each step and keeping only the remainder keeps the numbers small enough to do in your head.
The leap year adjustment
80 + 20 + 14 + 4 + 0 = 118. February of the leap year 1980 takes away 1. Without it, the answer would be 1 day late.
The 2000s
2000 was a leap year, so January takes the −1 adjustment. 1900 was not, so January and February 1900 need no correction.
5 dates that always share a weekday
April 4, June 6, August 8, October 10 and December 12 fall on the same weekday every year: a Saturday in 2026. Mathematician John Conway built his Doomsday rule on these anchor dates; find this year's weekday for them, then count to your birthday.
Why Does Your Birthday Fall on a Different Weekday Each Year?
Your birthday falls on a different weekday each year since a year is not a whole number of weeks. 365 days is 52 weeks and 1 day, so a birthday moves 1 weekday later each year, and a leap year's 366 days move it 2. The chart follows a 15 August birthday from 1990 to 2018.
Born on Wednesday, 15 August 1990
The birthday returns to Wednesday at ages 11, 17, 22, 28: gaps of 11, 6, 5, 6 years. Between 1901 and 2099 the calendar repeats every 28 years, so this pattern repeats from age 28.
Fewer births on weekends
US birth records show fewer births on Saturdays and Sundays. Planned caesarean sections and inductions are mostly scheduled on weekdays, and a National Center for Health Statistics (NCHS) report on 1999 births named Tuesday the most common day.
Famous birth weekdays
- Marie Antoinette: Sunday, 2 November 1755
- King Bhumibol Adulyadej of Thailand: Monday, 5 December 1927
- Kofi Annan: Friday, 8 April 1938
- Muhammad Ali: Saturday, 17 January 1942
Common Mistakes When Finding Your Birth Weekday
There are 6 common mistakes when finding your birth weekday, including swapping the day and month, skipping the leap year adjustment and using this year's birthday.
Swapping day and month
✕ 03/04/1995 read as March 4: Saturday
✓ In the UK and Australia it is April 3: Monday
Skipping the leap year adjustment
✕ 14 February 1980 without −1: Friday
✓ Take 1 away in January and February: Thursday
Using this year's birthday
✕ "My birthday is on a Friday, so I was born on a Friday"
✓ Birthdays move 1 or 2 weekdays a year
Mixing time zones
✕ Converting an 11:30 pm New York birth to London time
✓ Use the local date on the birth certificate
Old Julian dates
✕ George Washington's recorded "11 February 1731"
✓ Gregorian 22 February 1732: a Friday
Negative remainders
✕ −11,122 mod 7 = −6, stepping backwards
✓ Add 7: the remainder is 1, step forward
Frequently Asked Questions
How Do I Calculate My Birth Weekday from My Date of Birth?
To calculate your birth weekday from your date of birth, add the last 2 digits of the year, a quarter of them, the day, a month key and a century key, then divide by 7 and read the remainder. A remainder of 1 means Sunday, 2 Monday and so on to 0 for Saturday. For 17 January 1942: 42 + 10 + 17 + 1 + 0 = 70, and 70 ÷ 7 leaves 0, so the answer is Saturday. Subtract 1 for January and February of a leap year.
What Day of the Week Was I Born?
You were born on the weekday that your date of birth fell on in the Gregorian calendar, from Monday to Sunday. Enter your date of birth in the calculator above to see it, along with your birth-month calendar and the weekdays of your next 8 birthdays. Someone born on 15 August 1990 was born on a Wednesday.
How Can I Find Out What Day I Was Born?
You can find out what day you were born in 4 ways: an online calculator, a printed calendar for your birth year, the key value method by hand or a spreadsheet. In Excel or Google Sheets, put your date of birth in A1 and use =TEXT(A1,"dddd"). The calculator on this page is the quickest and checks leap years for you.
What If I Was Born on a Monday?
If you were born on a Monday, the old English rhyme says "Monday's child is fair of face". In Thailand, Monday's colour is yellow, which is why yellow shirts honoured King Bhumibol Adulyadej, born on Monday, 5 December 1927. Among the Akan people of Ghana, a boy born on a Monday is traditionally named Kwadwo and a girl Adwoa. These are customs and folklore, not predictions.
What Does Being Born on a Friday Mean?
Being born on a Friday means, in the "Monday's Child" rhyme, that you are "loving and giving". In Akan naming, a Friday-born boy is Kofi and a girl Afua: Kofi Annan, the former United Nations Secretary-General, was born on Friday, 8 April 1938. The meaning is cultural tradition; the weekday says nothing scientific about personality.
Does My Birthday Fall on the Same Weekday Every Year?
No, your birthday moves to a different weekday each year. A common year has 365 days, which is 52 weeks and 1 day, so the birthday moves 1 weekday later. When a February 29 falls in between, it moves 2. A 15 August birthday was a Wednesday in 1990 and a Thursday in 1991.
How Often Does My Birthday Fall on the Day I Was Born?
Your birthday falls on the weekday you were born 4 times in every 28 years, for dates between 1901 and 2099. The gaps follow a 6, 11, 6 and 5 year rhythm in some order. Someone born on Wednesday, 15 August 1990 had a Wednesday birthday at ages 11, 17, 22, 28. A February 29 birthday repeats its weekday once every 28 years.
Can I Find My Birth Weekday Without Knowing My Birth Time?
Yes, you can find your birth weekday without knowing your birth time. The weekday depends only on the date. Birth time matters in 1 case: a birth close to midnight in another time zone, where the local date on the birth certificate is the one to use.
What Day Was I Born If I Was Born on February 29?
If you were born on February 29, enter that date and the calculator finds the weekday the same way as any other date. February 29, 2000 was a Tuesday. Your real birthday returns every 4 years, and it lands on the weekday you were born every 28 years: the next Tuesday, February 29 after 2000 is in 2028.
Does the Calculator Work for Dates Before 1900?
Yes, the calculator works for dates back to October 15, 1582, the first day of the Gregorian calendar. Marie Antoinette, born on 2 November 1755, was born on a Sunday. Britain and its colonies switched to the Gregorian calendar in 1752 and Russia in 1918, so older records from those places use Julian dates that need converting first.
Can I Find the Day of the Week Someone Else Was Born?
Yes, you can find the day of the week anyone was born. Enter their date of birth in place of yours: a parent, a child, a partner or a famous person. Muhammad Ali, born on 17 January 1942, was born on a Saturday.
Find the day you were born
Enter your date of birth and the what day was I born calculator shows your birth weekday, your birth-month calendar and the weekdays of your next birthdays.
Find my weekday