Day of Week Calculator
Find out which day of the week any date falls on.
What is Day of Week?
A quick calendar lookup: the weekday for any historical or future date, with extra context like day-of-year and remaining days.
How it works
The native Date object's getDay() is reliable for the full Gregorian range browsers support, including dates before 1970.
- Enter your input. Type or paste your input into the field above — the tool responds instantly.
- Review the result. Output updates live as you type. Everything runs entirely in your browser.
- Copy or download. Use the Copy button to grab the result, or Download to save it as a file.
Examples
Meeting day check
August 26, 2026 is a Wednesday — confirm which weekday any past or future date falls on before scheduling.
Common mistakes
Off-by-one at month boundaries
Dates near month or year ends are where weekday mistakes happen — the calculator handles every boundary including leap years.
Frequently asked questions
Which weekday numbering is used?
Both — Monday-first (ISO) and Sunday-first (US) indices are shown so results match whichever system you use.
Does it work for dates far in the past?
Yes, the Gregorian calendar is projected back correctly, including century leap-year rules.
Can I find the day for a whole month?
The Date Range Generator lists every date in a range — pair it with this tool's logic if you need the full weekday grid.