Day Genius
Name the weekday of any date, in your head.
Common questions
I paid before and reinstalled. How do I get it back?
Open the Progress tab, find the Full method card, tap See what's included, then Restore purchase. It is free and works on any device signed in to the same Apple Account.
Why does Day Genius give a different weekday than my calendar app for old dates?
Because it is using the calendar people actually had. Britain and its colonies skipped 3–13 September 1752 when they switched from the Julian to the Gregorian calendar, and before that every fourth year was a leap year with no century exception. Day Genius applies those historical rules; most calendar apps project today's rules backwards instead. See Reference › Before 1752 in the app.
Why won't the date picker let me choose 7 September 1752?
That day never happened. Those eleven days were removed from the calendar, so the picker skips them rather than offering a date that did not exist.
What does it take to master a step?
Three drills at 90% or better. The count is shown on the step's own button, so you can always see how many remain.
Which steps are free?
The first four: day numbers, mod 7, month codes, and combining them into a weekday. One purchase makes the remaining four steps and year flashcards available — not a subscription. The later steps, both games and the rest of the reference open as you master their prerequisites.
Can I start over?
Progress › Reset progress clears mastery, scores and your streak. To clear only accuracy and speed statistics while keeping everything you have earned, use Clear answer history just above it.
Do you collect any of my data?
No. There is no account and no server. Everything stays on your device — see the privacy policy.