Can I use this to find what day of the week I was born?

Yes. Enter your birth date and the page will return the weekday for that date.

Can I check a future date too?

Yes. The calculator works for past and future dates as long as the calendar date is valid.

How do I find the weekday from a date?

Enter the date in the form. The page immediately returns the weekday, the formatted date, and supporting calendar details such as the day of year.

What is the ISO weekday number?

ISO weekday numbers run from 1 to 7, where Monday is 1 and Sunday is 7.

When should I use a date calculator instead?

Use the general date calculator when your real task is finding the difference between two dates or adding and subtracting time from a base date.

Day of Week Calculator

To find the day of the week for any date, enter the date below. The calculator returns the weekday name (Monday through Sunday), the day-of-year number, and the ISO weekday using the Gregorian calendar, with leap years handled automatically — useful for birthdays, historical dates, and trip planning.

Enter one date

Pick the calendar date you want to check. The page returns the weekday immediately along with a few supporting date facts.

Date

Choose any valid calendar date to find the weekday for that day.

The calculation runs in your browser. If you copy the link, the selected date is stored in the URL.

Results update instantly as soon as the selected date is valid.

Weekday result

Review the weekday and a few supporting date facts below.

Choose a date to begin

As soon as you enter a valid date, the page will show the weekday and related details.

How this day of week calculator works

This page focuses on one narrow task: checking what weekday a single date falls on. It is useful when the real question is "what day was this?" rather than a broader date difference or countdown problem.

1. Enter the date you want to inspect

Use the date input for a birthday, anniversary, historical date, or future plan.

2. Let the page resolve the weekday

The calculator turns that calendar date into a weekday result and supporting details.

3. Use the supporting facts if needed

You can also review the day-of-year number, ISO weekday number, and whether the year is a leap year.

When to use this weekday calculator

This page is narrower than a general date calculator. Its job is to answer what weekday a single date falls on.

Questions like "what day of the week was I born" or "what weekday is this date" fit this page better than a broad two-date comparison tool.

If your real task is counting days between dates or moving a date forward or backward, the general date calculator is a better fit.

Weekday lookup is often enough for birthdays, events, and historical references, so there is only one date to enter.

Sources and references

This public reference covers the Gregorian leap-year rules that affect the day-of-year result.

NIST: Leap Years and Calendars

Reference for Gregorian leap-year behavior, which affects day-of-year context.

Day of week calculator FAQ

Can I use this to find what day of the week I was born?: Yes. Enter your birth date and the page will return the weekday for that date.
Can I check a future date too?: Yes. The calculator works for past and future dates as long as the calendar date is valid.
How do I find the weekday from a date?: Enter the date in the form. The page immediately returns the weekday, the formatted date, and supporting calendar details such as the day of year.
What is the ISO weekday number?: ISO weekday numbers run from 1 to 7, where Monday is 1 and Sunday is 7.
When should I use a date calculator instead?: Use the general date calculator when your real task is finding the difference between two dates or adding and subtracting time from a base date.

Related date tools

Use the weekday page for single-date lookup, then move to the broader date tools when the task becomes date difference, countdown, or workday logic.

Date Calculator

Move from weekday lookup into general date math such as days between dates or adding and subtracting time.

Open tool

Countdown Calculator

Switch to countdown mode when the real question is how much time remains until a target date.

Open tool

Business Days Calculator

Use a weekday-aware date page when weekends, workdays, or manual holidays affect the answer.

Open tool