I know this is silly, but here goes...If I have a pattern that says it is a 10" finished block and I want to make it a 12" finished block could I just add 2" to EVERY measurement in the pattern? Would that make it come out to a 12" block? If it says an 8" block I would just add 4" to all measurements right?
This sounds logical to me but I want to hear from the experts before I mess up a bunch of fabric and waste a lot of time. Thanks.

it rather depends on the type of block. which kind are you trying to make?

No. You are forgetting the seam allowances as you are talking about finished sizes.

Also, were you just planning on putting a border around each block? Or increasing each of the elements in the block to make the whole block larger?

If you want to add a border around each block to increase the FINISHED size from 10" to 12" then you need to add a 1.5" strip around each side.

10" + 1.5" + 1/5" less seam allowences (4 of them 2 each side of the 10" where joined to the strip and 1 each end of the strip to "finish" ) = 12" block

If you want to increase the size of each element within the block to make the whole block bigger then you need to work out the math for each individual element. If it's a 4 patch you can probably do this simply (because 4 is divisible by 2), but if it is a 3 or a 5 patch ... you will be working in other fractions.

What block are you trying to increase?

You need to add 2" to block, not all measurements. Not to every piece of block. Some will lend themselves easily to different sizes, some will need really odd sizes of the pieces to do it.

That won't work. A ten inch block won't easily translate into a 12" finished block without some strange measurements. It's much easier to change a 6" finished block to a 12" block because six evenly divides into 12 and 10 doesn't. It's also about how many pieces are in the block. Just adding 2" on each piece won't work as you need to allow for seam allowances. It's more complicated than you would first think.

It's not silly, but I'm afraid it won't work. Let's say you had a 10" finished block made up of 5 squares across and 5 squares down. Each square would be 2" finished. If you added 2" to every measurement in the pattern, your squares would finish 4". That would give you a 20" block!

If you want to increase from 10" to 12", you need to increase each piece by 20% (12-10=2; 2 divided by 10=.20 or 20%). So your 2" square would now be 2.4". Add a .5" seam allowance all around, and you would cut your squares 2.9".

If you want to increase 8" to 12", you need to increase each piece by 50%, so a 2" square in the 8" block would finish 3" in a 12" block.

That's probably as clear as mud!

Thank you all so much I'm sure glad I ask first. I didn't take into consideration everything that was involved. The block I was asking about is called diamond candy. It's a 10" block, I guess maybe adding the 2" borders will be my option for this block.

Thanks again everyone you sure saved me a lot of time and headaches.

There's really no clear answer, until we know what block you are doing .... parts of each may be correct, or wrong!! :)

Some 10" blocks may translate easy enough into a 12" ... while some would be horrendous, with almost impossible to cut measurements.

So, please do share what block pattern ... and I bet help will be on its way to you from many posters here! :)

Sorry ... I am not familiar with that pattern, and the name has me intrigued! Could you please post a picture or a link to the pattern?

It's in Quilter's World magazine February 2010 issue. Quilters-World.com Diamond Candy is the name of the quilt