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Crochet C2C (Corner-to-Corner) Calculator

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Created by: Ethan Brooks

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Plan your corner-to-corner crochet project with precision. Enter your finished dimensions, choose yarn weight and block type, and get total block count, diagonal row breakdown (increase, straight, decrease), and yarn estimates — with multi-colour support for graphghans.

Crochet C2C (Corner-to-Corner) Calculator

Crochet

Calculate blocks, diagonal rows, and yarn for C2C crochet projects

Finished Dimensions

Yarn & Block Type

Colour Planning

Note: These results are for guidance only and shouldn't be taken as professional advice. Always double-check with a qualified expert before making decisions.

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What is a C2C (Corner-to-Corner) Calculator?

A C2C Calculator helps you plan corner-to-corner crochet projects by computing the total number of blocks, diagonal rows, and yarn requirements. Corner-to-corner crochet works diagonally — you start with a single block in one corner and increase by one block per row until you reach the desired width, then decrease back down to a single block at the opposite corner.

C2C is one of the most popular crochet techniques for blankets and graphghans (picture blankets) because the block structure makes it easy to follow pixel-style charts. Planning the exact block count and row structure before starting ensures your project comes out the right size with enough yarn.

C2C Crochet Formulas

Blocks Across (Width): Finished Width ÷ Block Size

Blocks Down (Length): Finished Length ÷ Block Size

Increase Rows: Equal to the smaller of Width Blocks or Length Blocks

Straight Rows: |Width Blocks − Length Blocks| (zero for square projects)

Decrease Rows: Same as Increase Rows

Total Blocks: Width Blocks × Length Blocks

Total Yarn: Total Blocks × Yarn per Block (varies by yarn weight)

C2C Calculation Example

You want a 40 × 60 inch rectangular blanket in worsted-weight yarn where each C2C block measures approximately 1 inch.

  1. Width blocks = 40 ÷ 1 = 40 blocks
  2. Length blocks = 60 ÷ 1 = 60 blocks
  3. Increase rows = min(40, 60) = 40 rows (1 block to 40 blocks)
  4. Straight rows = |40 − 60| = 20 rows (stay at 40 blocks wide)
  5. Decrease rows = 40 rows (40 blocks back to 1 block)
  6. Total diagonal rows = 40 + 20 + 40 = 100 rows
  7. Total blocks = 40 × 60 = 2,400 blocks
  8. At ~1.8 yards per block = ~4,320 yards

Common Applications

  • Blankets & Throws — the most popular C2C project, from baby blankets to full-size bedspreads
  • Graphghans — pixel-art blankets where each block is a coloured pixel forming an image
  • Scarves & Cowls — narrow C2C panels make interesting diagonal-textured accessories
  • Cushion Covers — C2C squares sewn into pillow covers with a fabric backing
  • Wall Hangings — decorative panels worked in C2C for modern fibre art

Tips for Accurate Results

  • Crochet a test swatch of 5–10 C2C blocks to measure your actual block size before starting a large project.
  • C2C blocks tend to be slightly rectangular — measure both width and height of each block.
  • For graphghans, plan your colour chart on graph paper where each square represents one C2C block.
  • Keep tension consistent — C2C shows inconsistencies more than flat crochet because of the diagonal lines.

Frequently Asked Questions

What is C2C (Corner-to-Corner) crochet?

C2C is a crochet technique where you start in one corner of the project and work diagonally, increasing one block per row until you reach the widest diagonal, then decreasing until you finish at the opposite corner. Each 'block' is typically a cluster of double crochet stitches.

How do I calculate the number of blocks for a C2C blanket?

Divide your desired width by the block size (usually ~1 inch for worsted weight) to get blocks across, and do the same for the length. The increase section runs until you reach the shorter dimension in blocks, then you work straight diagonals before decreasing. This calculator handles all the maths.

How much yarn does C2C crochet use compared to regular stitches?

C2C typically uses 15–25% more yarn than a standard double crochet blanket of the same size because each block includes chain stitches and cluster stitches. The exact amount depends on your yarn weight and tension. Budget extra yarn when planning a C2C project.

Can I make a rectangular C2C project or only squares?

You can make rectangular C2C projects. After increasing to the shorter side's block count, you work 'straight' diagonal rows (increasing on one end and decreasing on the other) for the difference between width and length blocks, then decrease to finish. This calculator supports both square and rectangular shapes.

What yarn weight works best for C2C crochet?

Worsted-weight (size 4) yarn is the most popular for C2C blankets because it works up quickly with defined blocks. DK weight produces a softer, drapier fabric. Bulky yarn creates very fast projects but uses more yardage. Choose based on your desired finished feel and timeline.

Sources and References

  1. Craft Yarn Council, "Standard Yarn Weight System & Gauge Ranges", 2024
  2. The Crochet Guild of America, "Corner-to-Corner Crochet Technique Guide"
  3. Repeat Crafter Me, "C2C Graphghan Block Sizing Reference", 2024