What day of the week was I born on?

Enter your date of birth in the date field, or browse the calendar to your birth month and click the day. The tool names the weekday and shows the traditional Monday's Child line for it. Nothing is sent anywhere — the answer is calculated in your browser.

Does it work for dates in the future?

Yes. The weekday of a future date is fixed by the calendar, so you can check what day a wedding, a deadline or a birthday years ahead will fall on — the same way you can look one up in the past.

Why does an old date's weekday look wrong to me?

The calculator uses the Gregorian calendar for every date. Countries adopted it at different times — Britain and its colonies in 1752 — so for dates before then the historical Julian weekday can differ. The Gregorian weekday shown is the modern standard used to date historical events.

Which day does the week start on?

The grid starts each week on Sunday, the common United States convention, with Saturday and Sunday marked as the weekend. The weekday of a date does not change with that choice; it only changes which column a date sits in.

Is my date sent to a server?

No. The whole calculation runs in your browser from the date you pick. The only thing the tool reads from your device is today's date, so it can highlight today when it opens.

What does "day 61 of 2024" under the weekday mean?

It is the date's position in its year, counted from January 1 as day 1: the sum of the full months before it plus the day itself. March 1 is day 61 of 2024 because 2024 has a February 29, and day 60 of 2023, which does not. December 31 is day 366 of a leap year and day 365 of any other year.

Why does the grid show days from the previous and next month?

The grid is always 42 cells — 6 rows of 7 — so every month has the same shape. The first of the month is placed in its weekday column, and the cells before and after it are filled with the real days of the neighbouring months, drawn dimmed. In August 2026 the first 6 cells belong to July and the last 5 to September. Clicking a dimmed day selects it and moves the view to its month.

What happens if I type a date that does not exist?

The date field is parsed as a year, a month and a day, and a value is accepted only when the month is a real month and the day is no greater than that month's length. 2023-02-29 is not a real date, so the selection does not change; 2024-02-29 is, and resolves to Thursday, February 29, 2024.

Day of the Week Calculator — What Day of the Week Was I Born?

Day of the week

Reading today’s date…

Find the weekday for any date — your birthday, a date in history, or one years ahead — on a calendar you can browse.

What it does

Type a date or click one on the calendar and it tells you the weekday — Monday, Tuesday, whichever it is. The calendar browses to any month of any year, forward or back, so the same tool answers what day your birthday fell on, what day the Fourth of July landed on in 1776, and what day March 2nd, 2035 will be. It opens on today, with today highlighted, so it doubles as a quick answer to what day it is right now.

What day of the week were you born?

Pick your date of birth and the weekday appears, along with the line the traditional Monday's Child rhyme gives that day — Monday's child is fair of face, Wednesday's child is full of woe, and so on. It is a folk rhyme, not a horoscope, but it is the thing most people are half-remembering when they ask what their birth day means. The same lookup works for anyone's birthday, and for the day any historical event fell on.

How the weekday is worked out

The weekday comes from the date alone, using the proleptic Gregorian calendar and plain integer arithmetic — not from your device's clock, beyond reading today's date to highlight it. That makes the answer the same for everyone, in every time zone, for any year. Leap years follow the full Gregorian rule: divisible by four, except centuries, unless divisible by four hundred, which is why 2000 was a leap year and 1900 was not.

Why the answer is the same on every device

The calendar module that answers the question is pure arithmetic, and its own header states the design: everything is proleptic Gregorian and computed with integer arithmetic — Sakamoto’s weekday algorithm for the weekday, Julian Day Numbers for counting days — so it is independent of the browser’s Date object, of the local time zone, and of the two-digit-year quirk. A date maps to the same weekday whoever runs it and whenever they run it. Evaluated when this page was built, at three fixed dates, the module returned Thursday, July 4, 1776; Friday, March 2, 2035; and Saturday, January 1, 2000. Those answers are static text here, and the tool in your browser reaches them by the same arithmetic rather than by asking the device. Internally each weekday is an index from 0 for Sunday to 6 for Saturday, and the name is the entry at that index in a list of 7 names: the Fourth of July 1776 resolves to index 4, which is Thursday. For the arithmetic itself — why a table of month offsets and three divisions settle the weekday of any year — read the guide How the day of the week is worked out.

Leap years, computed from the rule

Leap years are the one place the calendar’s arithmetic branches, and the tool applies the full rule stated above rather than the shortcut of dividing by four. Asked at build time about five fixed years, the engine says 2000 is, 1900 is not, 2024 is, 2023 is not, 2100 is not a leap year. February is the month that moves: it has 29 days in 2024 and 28 in 2023, and 28 in 1900 against 29 in 2000, which is the century exception doing its work. A leap day pushes every later date’s position in the year along by one, and the readout’s subline shows that position as the day of the year, counted from January 1 as day one. March 1 is day 61 of 2024 but day 60 of 2023, and December 31 is day 366 of 2024 against day 365 of 2023. The count is the sum of the month lengths before the date plus the day itself, so it differs between two years only when a February 29 sits between January 1 and the chosen day.

Counting days, and how the subline uses it

Behind the weekday sits a second piece of arithmetic. Each date is converted to a Julian Day Number — a continuous integer count of days — and the difference between two such numbers is the number of whole days between two dates. Month lengths, leap days and year ends all disappear into the count. With fixed inputs of 1990-05-17 and 2026-08-09, the engine returns 13,233 days, and adding that many days back onto the first date returns 2026-08-09: the two operations are exact inverses. The leap day shows up here too. From February 28 to March 1 is 2 days in 2024 and 1 day in 2023; stepping a single day forward from 2024-02-28 lands on 2024-02-29, from 2023-02-28 on 2023-03-01, and from 2024-12-31 on 2025-01-01. The tool reports this count in plain words relative to today, which is the one value it reads from your device. With a fixed reference date standing in for today, the phrasing comes out as “Today” for the same date, “Tomorrow” for the day after 2026-01-01, “in 12 days” for 2026-01-13 seen from 2026-01-01, and “13,233 days ago” for 1990-05-17 seen from 2026-08-09. There is no second date field: to count from a date other than today, note the two day-of-year figures or use the countdown timer linked below.

How the calendar grid is built

The month view is not a drawing of a month; it is a fixed rectangle of 42 cells — 6 rows of 7 — filled from the first cell onward with consecutive days. The engine finds the weekday of the first of the month, works out how many cells of the previous month are needed to push the first into its column, and then fills every cell by adding its offset to the first of the month. Days that belong to the neighbouring months are kept, flagged as outside the month and drawn dimmed, so every month is the same shape and the grid never changes height. For August 2026 with a Sunday-first week, the first of the month is a Saturday, so the first 6 cells hold the end of July — the first cell is Sunday, July 26, 2026 — the first of August sits in cell 7, 31 cells carry August, and the last 5 cells carry the start of September, ending on Saturday, September 5, 2026. The column headers read Su Mo Tu We Th Fr Sa. The grid builder accepts a different starting day — Monday-first would put that same first of August in cell 6 — but the tool fixes Sunday, so a date’s column is always its weekday index. The arrows above the grid step the view by one month or one year and roll the year at both ends: one month after December 2024 is January 2025, and one month before January 2024 is December 2023.

How to read the display

The stage at the top shows four things, each derived from the selected date and nothing else. The small label says Weekday or Weekend: a date is a weekend when its index is 0 or 6, that is a Sunday or a Saturday, so 2026-08-01, a Saturday, carries the Weekend label and the stage takes the weekend accent, while the Fourth of July 1776, a Thursday, is labelled Weekday. The large word is the weekday itself. Beneath it the long form gives the full date — Thursday, July 4, 1776 — and a quieter line gives three facts: how far the date is from today in whole days, the date’s position in its year, and the rhyme line for the weekday. The engine holds exactly one line per day: Sunday’s child is bonny and blithe, and good and gay; Monday’s child is fair of face; Tuesday’s child is full of grace; Wednesday’s child is full of woe; Thursday’s child is far to go; Friday’s child is loving and giving; Saturday’s child is works hard for a living. Under the stage, the date field jumps to any date you type, and Today returns both the selection and the visible month to the current date. In the grid, the weekend columns are tinted, today is outlined, the selected day is filled, and the dimmed numbers at the edges are real days of the neighbouring months — clicking one selects it and moves the view to that month.

What the tool does not do

It reads the date only, never the time. Today is read in your browser after the page loads: the page is prerendered with no date baked in and shows a placeholder until the browser supplies one, and no time zone enters the calculation at any point. It converts between no calendars; every weekday is the proleptic Gregorian one, as the note on very old dates explains. It rejects dates that do not exist. The date field is parsed as a year, a month and a day, and a value is accepted only when the month is a real month and the day is no greater than that month’s length, so 2023-02-29 yields nothing and the selection stays where it was, while 2024-02-29 is accepted and resolves to Thursday, February 29, 2024. It does not offer a Monday-first week, does not mark holidays, and does not remember the date you picked: close the page and it opens on today again. Nothing is sent anywhere — the whole calculation runs on your device.

Common misreadings

Day 61 of 2024 is a position, not a count of weeks or a date code: it is the number of days from January 1 to the selected date, both included. The dimmed numbers at the start and end of the grid are not disabled; they are the neighbouring months’ days, present because the grid is always 42 cells. The weekend accent follows the column — Saturday and Sunday — and says nothing about public holidays or working days in any country. The rhyme is a traditional folk verse keyed to the weekday; the engine stores one line per day and shows the one for the index, and nothing else is read into the date. A birthday on a leap day is an ordinary date to the engine: Thursday, February 29, 2024 is day 60 of its year, and the grid for February 2024 carries 29 days. And for dates before a country adopted the Gregorian calendar, the weekday shown is the modern Gregorian one, which can differ from what was written down at the time — see the note that follows.

A note on very old dates

Before a country adopted the Gregorian calendar, the weekday people wrote down could differ from the one shown here. Britain and its American colonies switched in September 1752, dropping eleven days to catch up; Russia did not switch until 1918. For dates in that era the calculator gives the Gregorian weekday, which is the modern convention and the one used to date historical events, but it is not what a diary of the day would necessarily have said.

Questions

What day of the week was I born on?: Enter your date of birth in the date field, or browse the calendar to your birth month and click the day. The tool names the weekday and shows the traditional Monday's Child line for it. Nothing is sent anywhere — the answer is calculated in your browser.
Does it work for dates in the future?: Yes. The weekday of a future date is fixed by the calendar, so you can check what day a wedding, a deadline or a birthday years ahead will fall on — the same way you can look one up in the past.
Why does an old date's weekday look wrong to me?: The calculator uses the Gregorian calendar for every date. Countries adopted it at different times — Britain and its colonies in 1752 — so for dates before then the historical Julian weekday can differ. The Gregorian weekday shown is the modern standard used to date historical events.
Which day does the week start on?: The grid starts each week on Sunday, the common United States convention, with Saturday and Sunday marked as the weekend. The weekday of a date does not change with that choice; it only changes which column a date sits in.
Is my date sent to a server?: No. The whole calculation runs in your browser from the date you pick. The only thing the tool reads from your device is today's date, so it can highlight today when it opens.
What does "day 61 of 2024" under the weekday mean?: It is the date's position in its year, counted from January 1 as day 1: the sum of the full months before it plus the day itself. March 1 is day 61 of 2024 because 2024 has a February 29, and day 60 of 2023, which does not. December 31 is day 366 of a leap year and day 365 of any other year.
Why does the grid show days from the previous and next month?: The grid is always 42 cells — 6 rows of 7 — so every month has the same shape. The first of the month is placed in its weekday column, and the cells before and after it are filled with the real days of the neighbouring months, drawn dimmed. In August 2026 the first 6 cells belong to July and the last 5 to September. Clicking a dimmed day selects it and moves the view to its month.
What happens if I type a date that does not exist?: The date field is parsed as a year, a month and a day, and a value is accepted only when the month is a real month and the day is no greater than that month's length. 2023-02-29 is not a real date, so the selection does not change; 2024-02-29 is, and resolves to Thursday, February 29, 2024.