This post is part of a series:  the Big Bed Quilt-Along.  We're sewing along February - April 2018, but you can use the resources anytime to help you make a large quilt.  Use hashtag #BigBedQAL to share your progress!

As soon as you try to choose a pattern for your bed quilt, you'll bump into the size question.  Don't assume anything about quilt size.  There are only loose standards in this area, which can make things rather confusing.  Size is a personal preference that deserves careful consideration.  Here's how to calculate your ideal bed quilt size.

To plan your ideal quilt size, you need a measuring tape, the bed in question and a note pad.

Measure Mattress

First, measure your mattress.  Measure the width and length, but don't worry about how thick it is.  My mattress is 61" x 79".  Draw a rectangle on your note pad and label the dimensions.  No need to draw it to scale!

Side Drop

How far do you want the quilt to fall on either side of the bed?  This is called "drop."  Measure from the top of the mattress to where you want the edge of the quilt to hit at the side of your bed.

You may wish to cover the bed's side rail or to show it.  You may wish to overlap with a bed skirt or even to make the quilt hit the floor.  This is why it's best to make these plans on the actual bed in question.  Answers will vary widely depending upon the architecture of the bed.

Add two long, thin rectangles to your quilt sketch, which signify the side drops.  Mine are 15" wide, for an 15" drop from mattress to below my bed's side rail.

Foot Drop

How far do you want the quilt to fall at the foot of the bed?  On a bed without a footboard, the quilt literally cascades off the end of the bed, just as with the side.  Here you'd probably want to plan the same drop as your side drop for symmetry.  

If your bed has a footboard and your quilt will be tucked under the mattress, measure your mattress thickness and add 4-6" to that.  This will provide a nice, secure tuck that won't come loose with kicking.

Add one long, thin rectangle at the bottom, to signify the foot drop.  Mine is 15" wide, to be tucked under my mattress.

Pillows

At the head of your bed, how do you like to style your pillows?  If you place pillows on top of the quilt, you don't need to add to your current dimensions.  Add extra size at the head of the quilt if you cover pillows or prefer a pillow tuck (where the quilt is tucked under the pillow edge quite a bit to create a neater look).

For a quilt that just covers the pillows, measure from the foot of the bed to the head of the bed with pillows in place.  Allowing your measuring tape to lay as a quilt would.  Compare this measurement to the measurement of simple mattress length.  The difference is your pillow addition.

For a pillow tuck, add 10" for your pillow addition.

Draw a long, thin rectangle along the top of your quilt sketch to signify the pillow addition, if any.  I needed 4" to cover my pillows without a pillow tuck.

Add it Together

Take a look at your quilt sketch.  Add up the total dimensions in width and in length.  This is your initial ideal bed quilt size.  Don't toss this sketch until you're finished with this project.  It will help you adjust your pattern and plan for backing. 

Shortcut, Anyone?

Are you just not going to do all that work?  Maybe you don't have access to the bed in person?  Ask yourself (or your giftee) to locate a blanket that fits the bed in the same way as an ideal quilt.  Measure that blanket to determine your quilt size.

Add Extra for Shrinkage

Here's something I didn't know - multiple readers report that shrinkage can transform a finished big bed quilt from perfect to disappointing.  I don't sew with prewashed fabrics.  Even if you do, battings typically induce shrinkage anyways.  Expect about 5% shrinkage.  Take your initial ideal quilt size and add 5% to determine your planned quilt size.

My initial size was 91 x 98".  With an extra 5% for shrinkage, I should shoot for a quilt about 96" x 103".

Pattern Adjustments

Rarely will you find a pattern in your precise planned quilt size.  Instead you will need to make adjustments, adding blocks, sashing and/or borders to bring your quilt up to size. 

As you make decisions on these matters, refer back to your quilt sketch.  Maybe your block's dimensions results in a quilt 2" narrower than you wanted.  Looking at your sketch, you realize that reduces your side drop by 1" on each side.  Maybe that's just fine?  Generally, you'll want to do the work to make your quilt slightly larger than planned, rather than smaller.  Your sketch will help you envision how the choices you are making will effect your enjoyment of the quilt.

Lastly, don't be shy about borders!  They really are the easiest way to hit an ideal quilt size without going crazy.  I haven't decided if I'm going to use borders on my Facing East big bed quilt.  It's pretty tempting at the bottom where the quilt will be tucked under the mattress anyways.  Perhaps a 6" border all the way around...

Choices, choices.  Do you have any size quandaries?