What the day logo
What the Day
LearnPracticePlayDailyGuides
LearnGuidesPracticePlayDaily challengeLeaderboardAboutContactPrivacy
Copyright © 2026 Jesper Kiledal
All rights reserved
☕Buy me a coffee
What the day logo
What the Day
LearnPracticePlayDailyGuides

July 20, 1787 was a
Friday

July 20, 1787 was a Friday — that’s 87,251 days ago. Below you can see exactly how to work the weekday out in your head with the Doomsday algorithm, along with a few other facts about the date.

Weekday
Friday
Day of year
201 of 365
ISO week
Week 29
Leap year?
No
Zodiac sign
Cancer
Days ago
87,251

How to solve: July 20, 1787

  1. 1
    Century anchor1700s→Sunday (0)
    Practice →
  2. 2
    Divide by 1287 ÷ 12→7
    Practice →
  3. 3
    Remainder of 1287 % 12→3
    Practice →
  4. 4
    Divide remainder by 43 ÷ 4→0
    Practice →
  5. 5
    Year's doomsday(0 + 7 + 3 + 0) % 7→3 → Wednesday
    Practice →
  6. 6
    Month doomsdayJuly→11th
    Practice →
  7. 7
    Distance20 − 11→9
    Practice →
  8. 8
    Final answer(3 + 9) % 7→5 → Friday

On this day in history

  • 1969Apollo 11 Moon Landing

Related dates

Day beforeJuly 19, 1787 — ThursdayDay afterJuly 21, 1787 — SaturdayOne year earlierJuly 20, 1786 — ThursdayOne year laterJuly 20, 1788 — Sunday
Want to be able to do this for any date in seconds? Read the guide or practice the algorithm.
Did you know? Did you know that 'Black Friday' refers to the day after the U.S. Thanksgiving, which marks the beginning of the Christmas shopping season?