🧮 How to Know How Many Rounds to Crochet + How Much Yarn You’ll Need
- Tiffany
- Jun 27
- 4 min read
Updated: Jun 28
Granny Square Top Series — Video 3
✨ A Quick Note
This post goes along with Video 3 of my Granny Square Top series. If you haven’t watched the first two videos yet, I recommend checking those out here:
📺 Watch the Video
Here’s Video 3! You can watch it right here without ever leaving the blog.
📝 Get the Worksheet
Want to follow along with a helpful worksheet that breaks everything down step-by-step?
🧵 Step-by-Step Guide (As Easy as Pie)
🔢 Step 1: How to Know How Many Rounds to Make
We’re going to use your swatch to figure out how many rounds you’ll need to crochet to get the size you want.
Using Your Measuring Tape, measure how tall each round will be so we know how much your square is growing with each round.
👉 If your swatch shows that each round adds ½ an inch to each side, that means 1 inch total is added to the width of your square every time you do another round.
1/2 inch on one side + 1/2 inch on the other side = 1 inch
Example:
Let’s say I want my top panel to be about 22.5 inches wide (that’s what the sizing chart says for a size Large).
** We are looking at the BUST measurement for width.
If each round adds 1 inch total to the square, then I’ll need to crochet around 22.5 rounds.
Because I can't make 1/2 a round in my granny square, I'm going to round up to 23 rounds.
🧠 Tip: Always round up unless you want your top to be more snug.
🧮 Step 2: How to Estimate Yarn for Your Square
Now, let’s figure out how much yarn each square will use.
Grab your worksheet. You should measure how many inches of yarn were used in Round 6, Round 5, Round 4 and Round 3. Please also find out how much yarn you used in Round 1 if you haven't already.
That information is going to be very important.
Just work Round 1, then mark the end of the round, undo the round and measure how much yarn was used in inches with your measuring tape.
✂️ Yarn Math (Don’t Worry—It’s Easy!)
Next, we will need to convert how many inches we measured in each round to yards. This is important because yarn skeins indicate how many yards of yarn are in the skein NOT how many inches of yarn.
Step 1: Take the inches of yarn and divide by 12 (that gives you feet)
✏️ Write it down on your worksheet.
Step 2: Take that number and divide by 3 (that gives you yards)
✏️ Write it down on your worksheet.
Repeat this conversion for Round 5, Round 4, Round 3 and Round 1.
🔄 Step 3: Calculate Yarn Growth
Now we figure out how much more yarn each round is adding.
Subtract the amount used in Round 5 from Round 6. Do the same for Round 4 to 5 and Round 3 to 4.
Add them all up, divide by 3, and boom—you’ve got your average 'yards of yarn' increased per round!
💡 Shortcut Formula Time!
Here’s a math trick to figure out how much yarn your full square will take:
🧵Total Yarn =
Don’t panic—just plug in your numbers!
Here’s my example:
I’m doing 23 rounds
Round 1 calculated 2.44 yards
Each round adds 1 yard
👉Total Yarn = ( 23 ÷ 2 ) × (2 × 2.44 + ( 23 - 1 ) x 1 ) = 309.12 yards
That’s one square. I’m making two squares.
309.12 x 2 = 618.24 rounding up to 620 yards
🧶 Step 4: How Many Skeins to Buy
Check your yarn label to see how many yards are in one skein.
Coboo (the yarn I’m using) has 232 yards per skein.
620 yards of yarn needed for project ÷ 232 yards of yarn per skein = 2.67 skeins of yarn needed for the project
So, I need to buy 3 skeins of yarn to be safe.
🎒 Materials You’ll Need
➤ Yarn: Coboo by Lion Brand – https://amzn.to/44kDDeP
➤ Crochet Hook H/8-5.00mm – http://bit.ly/40t5Vm9
➤ Scissors – https://amzn.to/45FgBlf
➤ Tapestry Needle – https://amzn.to/40sPQNp
➤ Measuring Tape – https://amzn.to/3HVTol4
➤ Calculator – https://amzn.to/3IhRlHW
➤Valari Maker Pillow – https://crafteaze.com/?ref=crochetwithtiffany932
⚠️ Affiliate Disclaimer
Some links above are affiliate links. If you purchase using these links, I may receive a small commission at no extra cost to you.It helps support the blog and my YouTube channel so I can keep creating helpful tutorials like this. Thanks for your support!
💖 Want More Help & Support?
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👀What's Coming Next...
Video 4 I'll be covering MODIFICATIONS! Different ways you can modify the neckline, length/width, and sleeves of your top to make it fit the way you want. You won't want to miss it!
Happy Crocheting!
~ Tiffany
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