Picture of Dodecahedron Calendar

I always thought the dodecahedron would make a perfect calendar.
Now updated for 2013.

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Step 1: Required Tools

To make the calendar you will need a scissors, X-acto knife or similar, tweezers, and a toothpick.

Step 2: Download Template

Download the template PDF from the link below the image preview box.  Print and cut out the twelve months.  Plain paper will work fine but a heavier, bonded paper will stay flat better.

To draw your own pentagons:
The pentagons I used are 2 inches on a side and there are three different rectangles for the months.  Months have 4, 5, or 6 rows plus one for the month name.
For the 7x7 square the side length is 2.12" and the center is 1.83" up from the bottom point of the pentagon.
For the 7x6 rectangle the size is 2.2" across, 1.9" vertical, and the center is 1.77" up from the bottom point.
And the 7x5 rectangle is 2.35" across, 1.68" vertical, and the center is 1.69" up from the bottom point.

These measurements will get the rectangle centered in the pentagon with the corners reaching the sides.  To make a larger or smaller calendar I'd recommend dividing these measurements by 2 and multiplying that by the length of the side of your pentagon.

The tabs measure about 1/2 inch in from each corner and are 1/3 inch wide.  The lines in the tab divide the tab in 3.

I had to use a CAD program, but more talented people could likely draw this out.
See my other instructable, Drawing a Pentagon.
2013.pdf903 KB

Step 3: First Fold

Picture of First Fold
Fold the trapezoid shapes back using the edge of a table or a metal ruler.

Step 4: Tabs and Slots

Picture of Tabs and Slots
Each trapezoid shape can be either a tab or a slot depending on which you need.

Step 5: Cutting Slots and Tabs

Picture of Cutting Slots and Tabs
To make the slot, cut line B between lines C with the X-acto knife.  To make a tab, cut both lines A and then fold the wings back behind to make a squarish tab.  Check the second image in this step for a hint on cutting the tabs.
paulsroom11 months ago
I like the idea of a dodecahedron calendar but fitting it all together gets awkward on the last couple of sides. So I've made an adaption which makes it far easier to put together. Accepting the fact that the calendar will need to move around a lot, I have made it in two halves that slot together. One half has tabs and the other half has slots. It's then very easy to stick the side together in each half and slotting them together requires no glue at all. In fact I prefer using double sided adhesive tape. I like the shape to be quite solid so I use 400gsm thick card which works very well. Although this is too stiff to go through the printer, adding the calendar months can be achieved by printing them on self-adhesive paper (I use white vinyl), then cutting them out in pentagon shape and sticking them on each month side. If anyone is interested I can send the template file in whatever format is desired.
dodecahedron calendar.jpg
Sorry, this should have said NOT move around. Although even with the unglued slotted state, it's still quite solid.
I've just finished making this, it took about 2 hours. It was relatively easy, putting the last piece on was pretty hard and it's kind of fragile. It turned out great though (:
netherstar (author) 3 years ago
Has anyone made this, or are the instructions too hard to follow?
can you just make it a perpetual one? i mean that can be used for many years???

netherstar (author)  alltootechnical4 years ago
I've made a dodecahedron out of 1/2 inch thick foam pieces.  Looks pretty good but then you'd be stuck "sticking" months on each side cut from paper every year.  Some of the spray-on adhesives are temporary, but it would be an un-godly mess.  You'd be spraying it, picking it up, then unsticking your fingers to set it down in the overspray.  Then picking up the next month with sticky fingers.

Making something permanent would be even more difficult.  Perhaps writing out the months with day one in the upper left corner in each month.  Then you would need some temporary way of marking which column is Sunday.
ChrysN4 years ago
Cool, that would look great on my desk.
paperrhino4 years ago
There are alternative additional approaches and templates for similar calendars:
     - dodecahedron calendar template that is cut out in one piece as opposed to 12 separate pieces
     - completely origami version that doesn't require tape or cutting
     - rhombic dodecahedron version that doesn't require tape or cutting
     - a flat star calendar assembled from 12 separate folded pieces

The 2010 version of each of these is available from the following link:

netherstar (author)  paperrhino4 years ago
I did visit the site you listed.  I like the rhombic version but this one will sit on my desk.  Personally, I like this one because I designed it.  I didn't have to go somewhere to be instructed how to build it. 
I plan on updating the site by November for 2011.