Can I check historical dates?
Yes, within PHP’s supported Gregorian date range.
Day of Week Calculator
Enter any date to learn which weekday it falls on, plus whether it is a weekend day.
Find the weekday
Choose a date to see the full weekday name and related calendar details.
About this calculator
How to use Day of Week Calculator, plus the formulas and logic behind the results.
Tool description
The Day of Week Calculator tells you the weekday for any valid Gregorian date. It is handy for scheduling, history questions, and checking weekend alignment.
How to use
- Enter the date you want to check.
- Select Calculate to see the weekday and related details.
Formulas & reference
weekday_name = date → day nameISO weekday N = 1 (Monday) … 7 (Sunday)weekend = N ≥ 6
Weekday details
- Full English weekday name
- ISO weekday number (Mon=1 … Sun=7)
- Weekend vs weekday flag
Calculation logic
The date is parsed as Y-m-d and formatted with weekday tokens. ISO N drives the weekend check used elsewhere in Time & Date tools.
Results use the Gregorian calendar. Historical calendar reforms before widespread Gregorian adoption are not adjusted.
Day of Week Calculator FAQ
Common questions about this calculator and how to use the results.
What about future dates?
Future dates are supported the same way as past dates.
Is Sunday day 0 or 7?
This tool uses ISO numbering: Sunday is 7.
Does locale change the day name language?
Day names are shown in English on this site.
How do I know if it is a weekend?
Saturday and Sunday are flagged as weekend days.
Is this affected by timezones?
Only the calendar date matters; no clock time is used.
Can leap days change weekdays?
Leap days shift subsequent weekdays by one day like any extra calendar day.
What calendar system is used?
The proleptic Gregorian calendar via PHP DateTime.