What day of the week was July 20, 1969? It was a Sunday, the day of the first Moon landing. The Day Name Finder gives you the weekday for any calendar date from year 1 to 9999.
It helps with birthdays, anniversaries, deadlines, and history homework. You pick a date and read the day name, the weekday or weekend label, and the week position.
Table of Contents
- What the Finder Does
- How to Use It, Step by Step
- How the Day Is Found
- Worked Examples
- How to Read the Results
- Checking the Answer by Hand
- Limitations and Assumptions
- FAQs About the Day Name Finder
What the Finder Does
The tool takes one date and returns its weekday. It updates when you change the date.
- Day of Week shows the full name, from Sunday to Saturday.
- Type (Sat, Sun = Weekend) shows Weekend for Saturday and Sunday, and Weekday for the rest.
- Day Number (Monday = 1) shows a position such as 1 / 7, where Sunday is 7.
- The report box repeats the date and adds a line for the day class and the week position.
- Copy Report copies that report as text.
How to Use It, Step by Step
- Click the Target Calendar Date field. The sample date is 2026-08-10.
- Pick a date from the calendar picker, or type the month, day, and year.
- Read the three cards for day name, type, and day number.
- Read the Calendar Day Analysis Report for the same facts in text.
- Press Copy Report to copy the report. The button briefly reads Copied, or Copy blocked if your browser refuses.
How the Day Is Found
The tool reads the year, month, and day you picked. It then runs pure calendar math in UTC, so your time zone and daylight saving cannot change the answer.
Year, Month, Day (UTC)→Weekday Index 0 to 6→Name From List=Day Name
- Index 0 is Sunday and index 6 is Saturday. Indexes 0 and 6 are labeled Weekend.
- Day Number equals the index, except Sunday shows 7 instead of 0.
- Leap years are handled by the calendar math, so 2024-02-29 is a valid date.
- Impossible dates and years outside 1 to 9999 are rejected with a message.
Worked Examples
These are the outputs for five explicit dates.
| Date | Day of Week | Type | Day Number |
|---|
| 2026-08-10 | Monday | Weekday | 1 / 7 |
| 2026-12-25 | Friday | Weekday | 5 / 7 |
| 2024-02-29 | Thursday | Weekday | 4 / 7 |
| 2000-01-01 | Saturday | Weekend | 6 / 7 |
| 1969-07-20 | Sunday | Weekend | 7 / 7 |
For 1969-07-20, the report heading reads "CALENDAR DAY ANALYSIS: SUNDAY". The date line reads "July 20, 1969 (1969-07-20)", and the position line reads "Day 7 of 7 (Monday = 1, Sunday = 7)".
How to Read the Results
Day of Week is the answer most people need. The report repeats it in the heading and on its own line.
Type treats Saturday and Sunday as the weekend. The report says "Weekday (Monday to Friday), public holidays are not considered", so a Weekday is not always a business day.
Day Number counts from Monday as 1 to Sunday as 7. It is a position in the week, not a day of the month or year.
Checking the Answer by Hand
Weekdays repeat every 7 days, so you can check any answer with one subtraction. Count the days between two dates, then divide by 7 and keep the remainder.
From Monday, 2026-08-10, to Friday, 2026-12-25, is 137 days. Dividing 137 by 7 leaves a remainder of 4. Four days after Monday is Friday, which matches the tool.
The days between dates calculator counts the gap for you. Use the week number finder to see which week of the year a date falls in. To count work days only, try the business days calculator.
The leap year checker explains why February has 29 days in some years. If you need a different date layout, the date formatter can help. You can find more in the unit and time converters hub.
Limitations and Assumptions
- The week starts on Monday for Day Number. Some countries start the week on Sunday.
- Weekend means Saturday and Sunday only. Some regions use a different weekend.
- Public holidays are not considered, and the tool has no business-day logic.
- Dates before 1582 use the proleptic Gregorian calendar, with a note on screen. Historical Julian dates can fall on a different weekday.
- A cleared or incomplete date shows a message, and all three cards read N/A.
- Years outside 1 to 9999, and dates such as February 30, get a message instead of a result.
FAQs About the Day Name Finder
What day of the week was 2000-01-01?
It was a Saturday. The tool shows Weekend and Day Number 6 / 7.
Does my time zone change the answer?
No. The answer comes from the year, month, and day alone. It matches the calendar date you picked, even on daylight saving change days.
Why does Sunday show as day 7?
The tool counts Monday as 1 and Sunday as 7. The code itself counts Sunday as 0, and the tool changes that for display.
Can I find the day for a past birthday?
Yes. Pick the birth date, such as 1990-05-15, and read the day name. For ages, use the age calculator instead.
Does it handle leap days?
Yes. You can pick 2024-02-29 and get Thursday. A date like 2023-02-29 does not exist, so the tool shows an error message.
Does a Weekday label mean the office is open?
No. A Monday that is a public holiday still shows as Weekday. Check a holiday calendar for that.
This calculator gives general estimates only and is not professional advice. Reviewed for general accuracy by Prof. Dr. Khalil Mudassar, PhD.