Day of Week Pro

Features

Quiz Mode

Test your day of the week knowledge against random dates. If you need help, a simple tutorial waits nearby.

Learn Mode

Look-up the day of the week to certain dates. A five-step tutorial is available on how to calculate in your head.

Multi-Lingual

Switch easily between English, Spanish, French & German.

Dashboard

Track your progress with colorful visual elements. Share your successes via email or social media.

Size-Friendly

Works well on a large tablet (iPad Pro/Galaxy Tab) down to a small phone (iPhone SE/Google Pixel).

Dark Mode

Easy to operate in regular or dark mode.

Crafted specifically for each platform

Apps are hand-written using the latest native IDEs & technologies: Jetpack Compose & SwiftUI.

Frequently Asked Questions

Did you think up this method?

No, this method implements the "Doomsday Algorithm" by British mathematician John Conway with improvements by Michael K. Walters and Chamberlain Fong. Compared to other day-of-week calculation methods, this one requires the least amount of blind memorization, hence a speedier answer.

How should I begin?

A good place to start is by limiting the centuries to the one containing your birthyear. As you get comfortable, add other centuries to your skillset.

Why can`t I learn dates before 1600?

Prior to 1600, there was a switch from Julian to Gregorian calendars due to differences between a solar & calendar year. During that time, Thursday 4 October 1582 was followed by Friday 15 October 1582, advancing the calendar by ten days overnight. Therefore, the "Doomsday Algorithm" cannot be used for dates prior to 15 October 1582.

Why doesn't Wikipedia have something for every date?

Good question. We can only display information that Wikipedia gives to us. Even though the Wikipedia website may have information for a particular date, that information may not be available through the WikiAPI json feed.