Herringbone Half Square Triangle Baby Quilt

This is my all time favorite quilt I ever made. Probably because it was the first quilt I made for my first child and there's a certain sentimental attachment in that.

It's yellow because I picked out the fabric when I first found out I was pregnant and then I got terrible morning sickness so I didn't finish it until I was in my third trimester.

But also because it came out looking just plain awesome.

• It's composed entirely of half square triangles.
• Each half square triangle unit is half print fabric and half white.
• The half square triangle units are arranged into columns so that on the horizontal seams of the finished quilt top, print edges touch print edges and white edges touch white edges.
• Every other column is offset so that on the vertical seams of the finished quilt top, print edges touch white edges.

The most common question I get about this quilt is "what pattern did you use?"

Here's the thing. I didn't use a pattern. I designed it myself by playing around with ways I could arrange half square triangles until I found an arrangement of pieces I liked and then I got to sewing it.

But since people just kept asking, I wrote one. This particular quilt uses charm squares (that I cut myself from standard yardage because I wanted this to ultimately be a quilt you could make with charm squares) and a block variation from the group based on a classic Streak of Lightning block. Click here to get the Half and Half Quilt Pattern + eBook.

How many fat quarters do I need for a quilt top?

Often I find myself purchasing a fat quarter bundle and then designing a quilt that fits the amount of fabric I have to work with. I don't like to have a lot of scrap fabric left over so I try to make the biggest quilt that the bundle I purchased allows for. Different bundles come with different amounts of fabric.

I made myself a little cheat sheet so that I can estimated what size quilt I'm going for based on how many fabrics are in my fat quarter bundle.

This cheat sheet assumes that you use the fat quarters whole with 1/4 seam allowance. It's not a realistic way to make a quilt as it doesn't account for selvedges. It's just a place to start estimating from.

• You're probably going to want to cut up your fat quarters into smaller pieces. Every time you cut you need a little bit more fabric to account for additional seam allowance.
• There might be fabrics you don't like or might not want to use as much of.
• If you don't have enough fat quarters for the quilt top you want to make, mix in some coordinating solids or neutrals. Half prints from a fat quarter bundle + half white is one of my favorite fabric combos.
• If you've got more fat quarters than you need for the quilt top you want to make, you can work extras into the backing or binding.

Notice that Queen and Double (Full) size need the same number of fat quarters. Places like Pottery Barn usually don't even differentiate between the two sizes.

I'd like to do the math

Here's what you need to know to get started:

• What size battings are available to you. I've got a cheat sheet for that here.

• How much overage you want around the edge of your quilt top when you sandwich it with the batting and backing. I like 2 inches on each edge, 4 inches total for the width and 4 inches total for the length.
• The size of a fat quarter. I used 22 inches wide, 18 inches long, and a 1/4 inch seam allowance. You could knock that down to 20 by 16 if you want to be more conservative with selvedges.

Here's how to do the math:

1. Width of the batting - your overage = A
2. Length of the batting - your overage = B
3. A / (width of your fat quarter - 2x seam allowance)
4. round your answer to 3 up to the next whole number and call that C
5. B / (length of your fat quarter - 2x seam allowance)
6. round your answer to 5 up to the next whole number and call that D
7. C * D = the total number of fat quarters you need at a minimum

What can I cut from a fat quarter plus how to do the math

How to use this chart

The numbers across the top represent the direction of your fat quarter that measures 22 inches (the width of your fabric).

The numbers down the right side represent the direction of your fat quarter that measures 18 inches (the length of your fabric).

Pick the column that represents how wide you want your cut piece to be (don't forget seam allowance) and pick the row that represents how long or tall you want your piece to be. The number where that column and row intersect is the maximum number of that size piece you can cut from one fat quarter.

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This chart makes a few assumptions that you'll need to account for:

1. You want to cut pieces that measure whole inches in both directions. If you need to cut pieces that are 6 and a quarter inches and you want to use this chart, round up to 7.
2. You can use every last inch of your fat quarter. Your fat quarter might have a selvedge that knocks an inch or two off the width or it might not be cut quite straight. Measure twice, cut once.
3. You're going to mess up while you're cutting. It happens. Make sure the number of squares or rectangles you can cut is a little bit higher than the number you absolutely need at a minimum.

I'd like to do the math

Here's what you need to know to get started:

• How wide is your fabric? 
  A typical fat quarter is going to be 22 inches. You may lose some for selvedge or wonky cutting.
• How long is your fabric? 
  A typical fat quarter is going to be 18 inches. You may lose some for wonky cutting.
• What size pieces do you want to cut? How wide? How long? 
  Make sure you add half an inch in each direction for seam allowance.

Here's how to do the math:

1. width of your fabric / width of your pieces
2. round that number down and we'll call that answer A
3. length of your fabric / length of your pieces
4. round that number down and we'll call that answer B
5. A * B = how many pieces you can cut