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Weekday for any calendar date

Day of Week Calculator: What Day of the Week Was Any Date?

Name the weekday for any calendar date, with day-of-year stats and a Doomsday walkthrough on your input. A Context line under the result cycles weekday facts by day of month. Inputs stay in your browser.

By Jeff Beem

Updated

01

Date

Day of week

Sunday

Sunday, July 12, 2026

Day 193 of 365 in 2026. 172 days left in the year.

The 28th Sunday of 2026 (28 of 52 Sundays; 24 left).

Context

Sunday is named after the Sun, one of the seven 'wandering stars' visible to the naked eye in antiquity.

02

Reference

Doomsday rule

Anchor weekdays on 4/4, 6/6, 8/8, 10/10, and 12/12, then apply the century anchor and year formula on the last two digits of the year. Leap years use 1/4 and 2/29 instead of 1/3 and 2/28 for January and February.

Formula (yy = last two digits of year)

Weekday walkthrough

Steps for Sunday, July 12, 2026:

1. Century anchor

For the 2000s, century anchor is Tuesday (d = 2)

2. Year (yy = 26)

a = ⌊26/12⌋ = 2, b = 26 mod 12 = 2, c = ⌊b/4⌋ = 0

3. Year doomsday for 2026

f = 6 → Saturday. So 4/4, 6/6, 8/8, and 12/12 fall on Saturday in 2026.

4. Offset to 7/12

Nearest doomsday in Jul: 7/11. Offset 12 − 11 = 1 → Sunday.

English day names

Sunday and Monday follow the Sun and Moon. Tuesday through Friday map Norse gods (Tiw, Woden, Thor, Frigg) onto the Roman weekday order from Mars through Venus. Saturday kept Saturn, the only Latin name left in everyday English. Wednesday’s silent “d” is a leftover from Woden’s day.

Reading the results

Section 01 is the answer. The day-of-year line is calendar position; the “nth Tuesday” line counts how many of that weekday have happened so far in the year, including today. Scroll to Reference when you want hand math on the same date.

Example: July 4, 1776

Enter 1776-07-04. The panel reads Thursday, July 4, 1776, with day 186 of 366 in that leap year and the 27th Thursday of the year (27 of 52; 25 Thursdays left). Handy when you need the weekday before quoting a founding-date fact.

Example: June 9, 2026

On 2026-06-09 the weekday is Tuesday. The stats block shows day 159 of 365 in 2026, 206 days left in the year, and the 22nd Tuesday of the year (22 of 52 Tuesdays; 30 still to come). Change the date and both lines move together.

When hand math disagrees with the picker

Leap Februaries shift January and February doomsday anchors. Century anchors jump every 400 years, which is where paper shortcuts usually break. Reference runs the full walkthrough on your selected date so you can see which step diverged.

Day of Week Calculator: weekday lookup and Doomsday walkthrough

Name the weekday for any calendar date, with day-of-year stats and Conway’s Doomsday Rule worked on your input.

What you get from one date

Pick a single date and the panel names its weekday, prints the long-form calendar date, and shows where that date sits in the year. You also get how many times that weekday has already occurred in the year (on June 9, 2026, the 22nd Tuesday) and how many are left. A Context line under the stats picks one of three facts for that weekday from the day of the month. Reference in section 02 runs the Doomsday steps on the same date and summarizes English day names. It does not add days, subtract days, or count business days between two endpoints.

Doomsday rule in plain terms

Each year has one weekday shared by 4/4, 6/6, 8/8, 10/10, and 12/12. Find that weekday with century anchor d and the last-two-digit pieces in f=(d+a+b+c) mod 7f = (d + a + b + c) \bmod 7, then walk forward or back from the nearest easy date in the month. Leap years nudge January and February anchors to 1/4 and 2/29 instead of 1/3 and 2/28. Step 1 in Reference names the century anchor; step 3 names that year’s doomsday after the formula.

Day-of-year and nth-weekday lines

On June 9, 2026, day 159 of 365 is calendar position from January 1. The “22nd Tuesday” line counts Tuesdays from the start of the year through that date, inclusive (22 of 52 Tuesdays in 2026; 30 left). Payroll accruals and broadcast calendars sometimes key off that count even when the plain weekday name is enough.

English weekday names

Sunday and Monday follow the Sun and Moon. Tuesday through Friday map Norse gods (Tiw, Woden, Thor, Frigg) onto the Roman order Mars through Venus. Saturday is Saturn’s day, the one name that stayed Latin in English. Wednesday’s silent “d” is a fossil from Woden’s day.

Day of Week Calculator FAQ

How do I find the day of the week for any date?

Pick a date in section 01. The dark results panel updates as you change the field: weekday name, long-form calendar date, day-of-year line, and nth-weekday count. Tap Today to reset to the current date.

What day of the week was July 4, 1776?

Thursday. Enter 1776-07-04 in the picker and the panel should read Thursday, July 4, 1776. The control accepts proleptic Gregorian dates from 0001-01-01 through 9999-12-31, the same calendar JavaScript uses for date math.

What is the Doomsday Algorithm?

John Conway’s Doomsday Rule names a weekday that 4/4, 6/6, 8/8, 10/10, and 12/12 share each year (with January and February using 1/3–1/4 and 2/28–2/29 in non-leap and leap years). The year term f=(d+a+b+c) mod 7f = (d + a + b + c) \bmod 7 uses century anchor d plus pieces of the last two digits. Reference in section 02 walks the same steps for your selected date.

Where do Tuesday, Wednesday, and Thursday get their names?

English weekdays mix Roman planet names with Norse gods. Sunday and Monday are Sun and Moon. Tuesday through Friday follow Tiw, Woden, Thor, and Frigg, lined up with Mars, Mercury, Jupiter, and Venus. Saturday kept Saturn. The Context line under the stats picks one of three facts for that weekday based on the day of the month.

Does this count days between dates or add business days?

No. This page only names the weekday for one date. For spans or rolling forward by N days, use the Day Counter or Date Calculator.

Time & Date Reference Note

Informational Use: These tools use standard date/time algorithms and your browser’s timezone data (IANA). Results are intended for general reference and planning only.

Verification Recommended: Time zone rules and daylight saving changes vary by region and year. For critical scheduling, payroll, or legal deadlines, confirm results with official sources.

Local Verification: Always confirm times, dates, and business-day counts with official sources or qualified professionals when stakes are high.

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