Calculate Yardage for An HST Quilt

Today, we'll be showing you the formula we use to calculate yardage and how to use it. In this particular example, we'll use HSTs, specifically two-at-a-time HSTs. But the formula will also work for plain squares, too. Adjust the amount of seam allowance added to C by ½" instead of 1". We've also created an accompanying worksheet/calculator which is available when you subscribe to our newsletter. You can find the form below.

E is the WOF. WOF is the measurement from selvedge to selvedge. Most fabric is supposed to be 43/45 inches. But err on the side of caution. If a fabric brand says 44" I always calculate it at 42". Usable WOF will differ from brand to brand. If you have the fabric on-hand, go ahead and measure it to find the exact usable WOF. For pre-cuts like FQ (fat quarter) or FE (fat eight), use 21" as the WOF.

F is for pre-cuts, like FQs, FEs, etc. F can also be used if you are using a pre-determined cut of yardage from your stash. Just complete the rest of the steps using the pre-cut calculations.

Now you need to decide if you are using yardage or pre-cuts. If you are using yardage, choose the number of fabrics(G). If using pre-cuts, leave G blank. In this example I will use yardage, so I will fill in 10(G).

1. Now you'll need to determine how many blocks in a row. 70"(A) / 4"(C) =17(H) blocks in a row. Rounding up or down to get to the closest desired quilt top size. I chose to round down, so the finished size of the quilt will be 68" instead of 70".
2. Next, calculate the number of rows in the quilt. 80"(B) / 4"(C) = 20(I) rows in a quilt. Round up or down as necessary.
3. Multiply H by I for the total number of HSTs in the quilt. 17(H) x 20(I) = 340(J) HSTs in the quilt top.
4. K is the number of squares that can be cut from one 5"(D) x WOF strip. 42"(E) / 5"(D) = 8(K). Round down to a whole number.

The next three calculations are for yardage only, skip to #8 for pre-cuts.

     5. L is the number of 5"(D) x WOF strips needed. 340(J) / 8(K) = 43(L). Round up to the nearest whole number.

     6. M is the number of 5"(D) x WOF strips to cut from each fabric. 43(L) / 10(G) = 5(M). Round up to a whole number.

    7. N is the numbers of inches needed of each fabric. 5(M) x 5"(D) = 25"(N). Round up slightly when purchasing fabric.

After all these calculations the answer is (10(G)) ¾-yard fabrics. I rounded (N) up to ¾-yard of fabric, giving me 2 extra inches to square off the fabric or pre-wash if desired.

For the pre-cut calculations, fill out 1-4 and then complete 8-10.

1. O is the number of 5"(D) x WOF strips that can be cut from each pre-cut. 18"(F) / 5"(D) = 3. Round down to a whole number.
2. P is the total number of 5"(D) squares that can be cut from each pre-cut. 4(K) x 3(O) = 12(P)
3. Q is the number of pre-cuts needed to complete the quilt top. 340(J) / 12(P) = 29(Q). Round up.

To make a HST quilt that is 68" x 80" with 4" finished HSTs, you will need 29(Q) FQs.

👉 This formula also works with plain squares, not just HSTs. Adjust the amount of seam allowance added to C by ½" instead of 1".

👉 Try to stick to numbers like 5" or 3½". Don't try for numbers like 1⅞" finished HST. It will make calculations and cutting trickier. If you are going to do in between sizes, remember that most cutting implements are in ¼" increments. Meaning that measurements that consist of ¼" increments will be easiest to cut.

👉 New to HSTs? You can find a tutorial here on how to make HSTs two at at time.

We've designed a pdf 'calculator' sheet of sorts to make it easier to calculate your yardage. It'll walk you through all the steps and tell you when to round up or down. You can print it off or fill it in on your computer. Want a copy? Just pop your email in the box below and hit subscribe!