Day of the Week Calculator

Find the weekday for any date — single or bulk lookup, fast and accurate. Instant • Responsive • Privacy-friendly, Free tool — no data sent anywhere

Single Date

Bulk Input (one date per line)

Output

Quick Answer Example

January 1, 2000 was a Saturday.

Use the Day of the Week Calculator below to instantly find the exact weekday for any date.

What this does

Enter any date (single or multiple) and this tool returns the day of the week (e.g., Monday). Accepts several common formats — ISO (YYYY-MM-DD), DD/MM/YYYY, MM/DD/YYYY and many textual date forms.

Key Features

Single-date calculation using the date picker.
Bulk processing — paste multiple dates (one per line).
Robust parsing and validation with clear error messages.
Readable formatted output and copy-ready results.
Mobile-first responsive layout and accessible elements.

How to Use

Pick a date with the date picker and click Calculate Day to get the weekday.
For multiple dates, paste one date per line into the Bulk Input textarea and click Calculate Bulk.
Results appear in the output box. Use Clear to reset.
If a line is invalid, an error will be shown for that line but valid lines will still be processed.

Real-World Use Cases

Confirm day-of-week for historical events, birthdays, deadlines.
Plan events, schedules, or recurring tasks.
Validate dates in data imports or spreadsheets.
Teaching or testing date-related algorithms and logic.

Benefits

Quick, accessible, and private — calculations run entirely in your browser. Minimal UI, maximum clarity: designed for speed and accuracy on phones and desktops.

Frequently Asked Questions

Which date formats are supported?Does it work offline?

Yes — all calculations run locally in your browser and no data is transmitted to servers.What about historical dates (before 1583)?Why does the output sometimes show a different normalized date?Can I paste a whole CSV into bulk input?

Yes — the parser reads one date per line. If your CSV has multiple columns, copy the column of dates or pre-process so each line contains a single date.Single Date

Calculate Day

Bulk Input (one date per line)
Calculate BulkClear

Output
Copy ResultsDownload .txt

Note: This tool is intended for everyday planning and learning. For legal, historical, or astronomical precision on historical calendars, consult specialist sources.

Disclaimer: All calculations are performed client-side and should be used for informational purposes only. For dates before 1583 or for locale-specific historic calendars, results may vary.

Accessible: inputs have labels and the output announces status updates. Mobile-friendly layout adapts to narrow screens.

Try : Days Until a Specific Date (Countdown Calculator)