What Day of the Week Was That Date?
Find the day of the week for any date, past or future. Also shows ISO week number, day of year, quarter, and leap-year status.
Runs 100% in your browser — nothing is uploaded.
That date is a
Wednesday
Wednesday, 12 August 2026
- Day of year224
- ISO week33
- QuarterQ3
- Leap yearNo
- Days in month31
Frequently asked
Does this work for dates before 1970?
Yes — JavaScript Date handles dates from 271821 BC to 275760 AD. Historical dates before 1582 use the proleptic Gregorian calendar, which may differ from the Julian calendar in use at the time.
What is "ISO week"?
ISO 8601's week numbering: weeks start Monday, week 1 is the one containing the first Thursday of the year. Most European and international standards use this.
Is 2100 a leap year?
No — divisible by 100 but not 400, so it's not a leap year. 2000 was (divisible by 400). This bug tripped up many programs at the turn of the millennium.
Related tools
- Date Format ConverterConvert any date into 12+ common formats: ISO 8601, RFC 2822, US MM/DD/YYYY, EU
- Age CalculatorEnter a date of birth to see age in years, months, days, hours, minutes, and sec
- Working Days CalculatorCount business days between two dates, excluding weekends and custom holiday dat
- Countdown TimerCount down to any date and time, second by second. Add a label and share the URL
- Date Duration CalculatorAdd or subtract any combination of years, months, weeks, days, hours, minutes, o
- Time Zone ConverterConvert a time between any IANA time zones. See offsets, live now, and multiple