One Big Granny Square Blanket – Free Crochet Pattern

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If you’re looking for a crochet project that’s relaxing, beginner-friendly, and makes a big impact — this One Big Granny Square Blanket is just the thing. Made from a single, ever-growing granny square, this pattern takes all the charm of traditional granny squares and makes it more exciting. It’s literally just one oversized granny square.

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Whether you’re brand new to crochet or looking for a relaxing TV project, this pattern is perfect for all skill levels. Let’s talk yarn, techniques, and creative ways to customize your very own heirloom-worthy piece.




What is a Big Granny Square Blanket?

The one big granny square blanket is exactly what it sounds like: one big, continuous granny square worked in the round until you reach your desired size. Unlike traditional blankets made from joining multiple squares, this version grows from the center out. It’s a timeless design that allows for a ton of creativity with colors and textures.

Plus, it’s one of the most beginner-friendly crochet patterns out there. Once you learn the basic granny square stitch pattern, it’s just a repeat. Seriously, it’s that easy!




Why You’ll Love Making the Granny Square Blanket

Beginner-Friendly: The pattern repeats after just a few rounds, making it easy to memorize.

Relaxing: Perfect for mindless crocheting while watching TV or listening to audiobooks.

Customizable: Switch up colors, add stripes, or go full-on rainbow!

Great Gift Idea: Make one for baby showers, birthdays, or just because.

Functional Decor: Use it to add a pop of color and texture to your living space.


Yarn Suggestions for a Big Granny Square Blanket

The best part about the large granny square blanket is that it works with just about any yarn weight, although worsted weight acrylic is the most popular.
Some of my favorite options include:

If you have a hard time choosing a color palette, try Herrschner’s Worsted 8 Multi-Packs! They have many options to fit your aesthetic!

If you’re looking for a thicker & quicker option, I like Lion Brand Hometown! It’s super bulky with good drape!


One Big Granny Square Crochet Pattern in rainbow stripes



How Big Should a Granny Square Blanket Be?

That’s totally up to you! But here are some size guidelines to give you a starting point:

Blanket TypeSize (inches)
Baby Blanket30 x 30
Lapghan40 x 40
Throw Blanket60 x 60
Twin Bed75 x 75
Queen Bed90 x 90

Just keep working rounds until it reaches the size you want—or you run out of yarn (let’s be honest, that happens a lot).

Color Ideas for Your Granny Square Blanket

Here’s where the fun begins! Granny squares are famous for their color versatility. You can go wild with your stash or plan a more intentional palette. Some ideas:

  • Scrapbuster: Use all your leftover yarn in random order.
  • Monochrome: Choose shades of one color (light to dark).
  • Bold & Bright: Rainbow stripes, color blocking, or high contrast.
  • Neutrals: White, beige, grey, and black for a modern home decor vibe.
  • Seasonal: Fall tones, winter blues, or spring pastels.

And don’t forget—you can change colors every round, every few rounds, or stick with a solid color for a clean look.

Tips for Success

  • Keep those corners consistent. Always (3 dc, ch 2, 3 dc) in each corner space.
  • Use stitch markers to mark your corners if you’re new to the pattern.
  • Block your blanket to make it nice and square, especially if it’s curling or rippling.
  • Weave in ends every few rounds so you’re not left with a huge task at the end.

Creative Variations

Want to spice things up? Try these ideas:

Add texture: Use puff stitches or bobbles in alternating rounds.

Add a fancy border: Try shells, picots, or pom-poms!

Join multiple large squares with contrasting seams.

Use gradient yarn cakes for a beautiful ombré effect.

How to Get the One Big Granny Square Blanket Crochet Pattern:

One Big Granny Square Crochet Pattern in rainbow stripes
how to get the

One Big Granny Square Blanket Crochet Pattern

Option 1: Continue scrolling for free pattern instructions on this site

Option 2: Purchase the ad-free PDF that includes tutorial photos from one of my shops



About the Materials

The One Big Granny Square Blanket was crocheted with 100% Cotton Worsted Weight Yarn, specifically I Love This Cotton. Good substitutes for this yarn are Knit Picks Dishie, Paintbox Cotton Aran, and Lily Sugar ‘n Cream. You can also use cotton blends, 100% Acrylic yarn, wool blends. Whatever yarns you prefer.

You will also need an H/8/5.00mm crochet hook, yarn needles hiding strings, and as an optional material: fabric for adding a backing. I would suggest a good minkie or standard fleece as it will be easy peasy to sew on. Plus, it’s soft and cozy warm.


The Crochet Pattern

Keep reading for a list of what you need to crochet the One Big Granny Square Blanket, including the stitch pattern instructions!

One Big Granny Square Crochet Pattern in rainbow stripes


Materials

Worsted Weight Yarn (#4)

  • Beige (MC) – 5oz (260yds)
  • Purple (A)- 2oz(105yds)
  • Pink (B) – 2oz(110yds)
  • Yellow (C) – 2oz(110yds)
  • Turquoise (D) – 2oz(110yds)
  • Aqua (E) – 2oz(110yds)

H/8/5.00mm Crochet Hook

Yarn Needle

Scissors

Optional Materials

Minkie or Standard Fleece


Gauge

3.5 CL + 3 ch-1 x 8 rows = 4”

Not critical: rows can easily be adjusted.


Finished Measurements

30” x 30” shown, but adjustable


Stitch Guide

arnd = around

ch = chain

dc = double crochet

sc = single crochet

sl st(s) = slip stitch(es)


Skill Level

Beginner


Pattern Written in U.S. Terms

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One Big Granny Square Crochet Pattern in rainbow stripes


Notes
  • Beginning chain 2 counts as the first stitch.
  • Blanket works from the center-out.
  • Where asterisks appear, repeat the instructions between them.
  • Where parenthesis appear within the instruction, work those stitches into the same space.
  • Optional: Add a fabric backing!
  • Included in the PDF: Stitch chart with black and white version on last page for color testing!


Special Stitches

Cluster (CL) – Place three double crochet in the same space.


Instructions

BLANKET

With Color A,

R1. Ch 3, join to form a ring: In ring, ch 2, 2 dc, ch 2, *3 dc, ch 2* 3X, sl st to top of beginning ch 2; Fasten if changing colors.

With Main Color,R2. Attach yarn to ch-2 space, (ch 2, 2 dc, ch 2, 3 dc) in same space as join, ch 1, *(3 dc, ch 2, 3 dc) in next ch-2 space, ch 1* 3X, sl st to top of beginning ch 2; Fasten if changing colors.

With Color B,

R3. Attach yarn to ch-2 space, (ch 2, 2 dc, ch 2, 3 dc) in same space as join, ch 1, 3 dc between CLs, ch 1, *(3 dc, ch 2, 3 dc) in ch-2 space, ch 1, 3 dc between CLs, ch 1* 3X, sl st to top of beginning ch 2; Fasten if changing colors.

With Main Color,

R4. Attach yarn to ch-2 space, (ch 2, 2 dc, ch 2, 3 dc) in same space as join, ch 1, (3 dc, ch 1) between CLs, *(3 dc, ch 2, 3 dc) in ch-2 space, ch 1, (3 dc, ch 1) between CLs* 3X, sl st to top of beginning ch 2; Fasten if changing colors.

Repeat R4 to desired size, alternating colors as desired. Blanket shown was repeated for 24 rows with a color change pattern of *A, MC, B, MC, C, MC, D, MC, E, MC* ending with MC.


BORDER

With Main Color,

Ch 1, 1 sc in each st and ch space around, sl st to join in 1st sc

If a decorative border is desired: count the number of stitches around the outside of the square and find a border pattern that matches that same stitch multiple.

Finishing
  • Block as desired (helps make it perfectly square and flat).
  • Secure and Hide All Strings.
  • Optional fabric backing (I suggest minkie or standard fleece): Lay blanket flat, wrong side up, and measure inside the border, cut fabric to same measurement and attach. You can attach it via sewing machine, hand sewing (fleece is very easy to push a needle through!), or if you’re using cotton yarn, you can attach a backing with heat bond tape. Heat bond tape can be used for other yarns, but be careful not to overheat the iron and melt or shrink the yarn.

That’s the One Big Granny Square Blanket Crochet Pattern!

One Big Granny Square Crochet Pattern in rainbow stripes



Don’t forget to share!

If you make a One Big Granny Square Blanket, I’d love to see it! Tag me on Instagram at @blackstone_designs or use the hashtag #OneBigGrannySquare so I can share your makes with the community.


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Written pattern and photographs © 2025 Sonya Blackstone of Blackstone Designs. Do not sell, share, or modify this pattern, but instead share the link to where the pattern can be found. You may sell items you make with this pattern. This pattern, as with all Blackstone Designs/Sonya Blackstone patterns, are not for educational use without written permission from the designer.  All rights reserved.

Sonya Blackstone is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.

Written pattern and photographs © 2025 Sonya Blackstone of Blackstone Designs. Do not sell, share, or modify this pattern, but instead share the link to where the pattern can be found. You may sell items you make with this pattern. This pattern, as with all Blackstone Designs/Sonya Blackstone patterns, are not for educational use without written permission from the designer.  All rights reserved.

Sonya Blackstone is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.

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