klswift

I love my 12". It is easy to use for a 9 or 10 with a bit of tape to mark it off.

Skyangel

I have square rulers from 2 1/2", 3 1/2", 4 1/2", 5 1/2", 6 1/2", 8 1/2", 9 1/2", 12 1/2", and 20 1/2". I think I mostly make 12" blocks so use the 12 1/2" the most for squaring up.

ManiacQuilter2

It depends on what you will use the most. I use an 8.5" square much more than I use my 12" square and very seldom do I use my 15" square.

Bjbaxter

I also have several sizes, but use my 8.5 size the most. I have have to replace it a couple of times since I have managed to chip away at the edge I use most.

wendiq

I have a 20" square ruler......while it is huge, I originally used it for squaring up T-shirts, it has come in quite handy and I'm not sorry I have it, however, I really don't need on that large....I also use my 12" and 10" more often......I also often use one that is 8.1/2" That seems go be a popular sized block and of course, any of these can be used for smaller blocks.

todiesmom

Thanks mhollifiel for that video....it is well worth watching...I sort of do this but tear off 16 or 17 inches then line up selvages and fold but cut the normal way. I think her way of doing it in reverse makes sense and is more accurate. i don't think I can cut 4 layers but I can certainly do 2. ....referring to site below:

https://www.youtube.com/watch?v=NoBKOv3Azzw

NJ Quilter

Love this analogy! I have a 16.5" but frankly, rarely use it. Had to buy it for a class and have maybe used it a couple of times since then.

I square up my units as I make them so rarely have a need to use a larger ruler just to square up a block. But as others have mentioned, buy a) what you can afford and b) the next size up from the most common size block you make. To square any unit, I measure from the seam line in the middle of the unit/block to the outside edge and trim as necessary.

My other other suggestion is to make sure that you buy the same brand square up ruler as the rest of your rulers. They are not all created equal. If you use brand x to do your primary cutting/measuring and brand y to square up - they measurements may not be consistent. You would think an 'inch is an inch' but it isn't.

bearisgray

I have laid my different rulers on top of each other to see if the lines match up.

In most cases, they do.

The one ruler that I actively avoid now is the "Quilter's Rule" with the thick grid lines because of the width of the lines. They also seem to "wear out" more quickly than some of the other brands.

beckyboo1

Got my square up ruler at Joann. It is 12" with markings at every 1/2" on down so I don't need multiple rulers for different size blocks.

quiltingnewf

Thank you to everyone who replied.... I really do appreciate the feedback, I wish I could buy all of the rulers, but like so many people these days, I have to watch my nickels (no more pennies in Canada). Lots of great advice, as always.

I do not have a Joann's where I live and until I read that post never even thought about checking for rulers at Michael's. Locally, my options are a small quilt shop, a national fabric store and a Michaels. I checked out the selection at Michaels and think I may wait for the 50% off coupon and get the 12 1/2 inch (or maybe get 2 coupons and buy a second smaller one too). I have not made blocks that large but looked thru my wish list of quilts to do and there are 2 that have larger blocks.
Thanks again