Find the weekday for any valid date and see its position in the month, quarter, calendar year, and ISO week calendar.
CalcRocket validates the date, applies Gregorian calendar rules, and uses shared date-only arithmetic to determine its weekday. Date-only values avoid time zones and daylight-saving changes, so the calendar day does not shift.
The result also calculates the ordinal day, month and year days remaining, quarter, and ISO week information from the same validated date.
January 1 is day 1. December 31 is day 365 in a common year or day 366 in a leap year.
day of year = days since January 1 + 1This convention excludes the selected date itself.
days remaining = days in year − day of yearISO weeks start Monday. Dates near New Year can belong to an ISO week-year different from their calendar year.
ISO week 1 = the week containing the year's first ThursdayThe quarter follows the calendar month.
Q1: Jan–Mar · Q2: Apr–Jun · Q3: Jul–Sep · Q4: Oct–DecAugust 13, 2026 is Thursday, day 225 of 2026, in ISO week 33 and Q3. There are 140 days left in the year.
January 1, 2021 is Friday. It belongs to ISO week 53 of ISO week-year 2020.
February 29, 2024 is Thursday. It is day 60 of a leap year.
Check the displayed ISO week-year around New Year; it may differ from the ordinary calendar year.
Month and year remaining counts exclude the selected date.
Saturday and Sunday are labeled Weekend; Monday through Friday are labeled Weekday.
Leap years normally occur every four years, except century years must also be divisible by 400. Thus 2000 was a leap year, while 1900 was not.
For historical dates, this calculator applies proleptic Gregorian calendar rules consistently, including dates before local Gregorian adoption. It does not reproduce every historical regional calendar.
Enter the calendar date and select Calculate. The weekday appears as the primary result.
You can enter a birth date here, or use the Birthday Calculator for birthday-specific details.
The calculator uses shared Gregorian date-only calendar arithmetic, avoiding time and timezone conversion.
ISO 8601 weeks start Monday, and week 1 is the week containing the year's first Thursday.
The first few January dates can fall in the final ISO week of the preceding week-year under the first-Thursday rule.
The day of year counts January 1 as day 1 and includes February 29 in leap years.
CalcRocket subtracts the ordinal day from the number of days in that year, excluding the selected date.
The result says Yes when the Gregorian year has 366 days and No when it has 365.
January through March is Q1, April through June Q2, July through September Q3, and October through December Q4.
Yes, within the date input's supported range, using proleptic Gregorian rules rather than local historical calendars.
No. The calculation uses a date-only value and does not require a time or timezone.
It uses the proleptic Gregorian calendar consistently.