The Magic Day: Calendar Tricks for Geeks

by Melanie and Jim

Amaze your friends! Astound your neighbors! Confuse your enemies! Calculate the day of the week for any date, all without consulting a paper OR electronic calendar!

Several years ago my dad, a brilliant man, told me about a calendar trick he used. The trick allowed him to figure the day of the week for nearly any date. While other people were still looking in their paper planners (back in the old days,) he already knew.


Original calendar layout Β jks Lola – | Noted dates by Jim and Melanie in IA

In 2014, Friday is the MAGIC DAY, a reference day around which the calendar trick revolves.

Let’s begin with the easy ones:
the 4th day of the 4th month and
the 6th day of the 6th month and
the 8th day of the 8th month and
the 10th day of the 10th month and
the 12th day of the 12th month

ALL fall on the same day of the week, the MAGIC DAY. In 2014 the Magic Day is Friday.
Note that for the EVEN numbered months starting in April, the day and month match up.

Besides those:
the 9th day of the 5th month and
the 5th day of the 9th month and
the 11th day of the 7th month and
the 7th day of the 11th month

ALL fall on the same day of the week, the MAGIC DAY. In 2014 the Magic Day is Friday.
Note how 5 and 9 match up [think “9 to 5”] and 7 and 11 match up [think “7-11”].

That leaves January through March. February and March are simple.

For February, the LAST day of the month is the Magic Day (Friday this year), regardless of whether or not it is leap year.

For March, since the LAST day of February is the Magic Day, the 7th, 14th, 21st, and 28th of March also fall on the Magic Day. Pi Day is the Magic Day!

January is more difficult, but because the last day of February is the reference day, the last day of January is the same day EXCEPT in leap years. In leap year it is the day before the reference day. For example, in 2012, a leap year, the last day of January was Tuesday, not Wednesday. (Go ahead, check the calendar and see.)

Once you know these rules, you can move backward or forward in any month to determine the day of the week. For example, my son’s birthday is on the Magic Day, and mine is two days later. This year his birthday is Friday, so mine must be Sunday.

The reference day progresses through the years. It becomes one day later every year, except in leap years when it advances two days. In 2011, the Magic Day was Monday, and it progressed two days to Wednesday in 2012. In 2013, it was Thursday, and in 2014, it is Friday.

These days when so many people carry smart phones, it may not be as useful as it used to be. But I don’t have a smart phone. I have a dumb phone, and I still use these rules. Do you think you are geeky enough to remember and use these rules?


21 thoughts on “The Magic Day: Calendar Tricks for Geeks

  1. Pingback: Fiesta Friday #10 | The Novice Gardener

  2. Alex Autin

    Despite my brain protesting loudly (it usually thinks that by lunch time it’s done enough for one day), I had to put the trick to test. It worked, every time!
    Now, if I’m ever without my smartphone…wait…did I say ‘ever without my smartphone’? Ok, no way that’s ever gonna happen…. πŸ˜‰

  3. Hilda

    Whether I actually make use of this information, it is good to know. Makes for great party conversation – like at one of our Fiesta Fridays get-together. I just hope I can remember it well enough to wow others.

    1. Melanie in IA Post author

      It took me quite a while to memorize it, but I have it down now! I still get tripped up on the January rule sometimes, but usually it doesn’t matter. πŸ™‚

  4. chefjulianna

    Oh Melanie, this is a great icebreaker to bring to Fiesta Friday!! Now, I have to let you know that most of the guests have had way too many Latin Lovers by this point in the party. I’m so glad you wrote this all down for us because some of them will need a little “refresher” in the morning! πŸ˜‰

  5. sabine

    what a nice idea you brought some party conversation instead of a cake! so little calories, yet not so easy to digest! But once you thought it through, great to small talk to warm up at a party!

  6. saucygander

    I love this! I don’t know if I’m geeky enough to remember all the rules (but it would be fun to try!), but I know just the friend who would memorise the full rules and then show of next time we meet, haha! Thanks for this post, really interesting! πŸ™‚

  7. Ngan R.

    Oh my gosh, I’m totally geeking out and printing this page so I can learn the rules. What fun! I am constantly asking myself what date falls on which day so having this memory trick will do wonders, I’m sure. Thank you for sharing this handy chart and all this info!

    1. Melanie in IA Post author

      I’ll admit, Steve, that this time of day I’m not as functional, so I can’t even read that! It looks a lot more comprehensive and possibly simpler, once learned, than my dad’s method above.

      Thanks for taking reading.


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