A pattern is a ratio wearing a specific size. Enter what the pattern makes, what you want instead, and its starting count, the new count comes back snapped to the stitch repeat, with the yarn scaled by area.
The Pattern and Your Size
Your Resized Start
150stitches
from the pattern’s 120 · 40×50 → 50×65 in
Start with 150 stitches and work rows to 65 in, measuring rather than counting.
- Unsnapped count150.0
- Real width at this count50.0 in
- Area change× 1.63
- Yarn, scaled4,063 yd
The Formulas
new stitches = pattern’s stitches × (new width ÷ pattern’s width), snapped to the repeatnew yarn = pattern’s yarn × (new area ÷ pattern’s area)Width scales stitches linearly; yarn scales by area, the resize mistake that strands blankets two skeins short. Length usually just means more rows; shaped patterns (toys, garments) scale every counted row, which is a redesign, not a resize.
Worked Example
A 40 × 50 in blanket pattern, 120 starting stitches over a 3 + 2 granny repeat, 2,500 yd: made as a 50 × 65 throw:
- Stitches: 120 × (50 ÷ 40) = 150 → snapped to 3n + 2 → 149.
- Yarn: 2,500 × (3,250 ÷ 2,000) = 4,063 yd: area grew 63% while width grew 25%.
- Rows: follow the pattern to 65 in instead of 50, row counts scale with your row gauge, so measured length beats counted rows.
What Resizes Cleanly, What Doesn’t
- Clean: blankets, scarves, wraps, dishcloths, anything worked flat in repeats.
- Careful: hats and mittens: scale the starting round, keep the crown math from the circle rules.
- Redesign: garments and amigurumi, where every shaping row is counted. Scale the gauge instead: a thicker yarn makes the same pattern bigger with no arithmetic.
Assumptions and Defaults
- Snapping prefers the nearest repeat-legal count, downward on ties.
- The yarn scale assumes the same yarn and stitch; changing weight too multiplies again by the new gauge ratio.
- Border yardage scales by perimeter, not area: add a skein’s grace on big scale-ups.
Resize Questions, Answered
How do I resize a crochet blanket pattern?
To resize a crochet blanket pattern, multiply the starting count by the new width ÷ the old width, round it to the stitch repeat, and work rows until you reach the new length. The example turns 120 stitches into 149 for a throw 25% wider, keeping the stitch pattern intact across the larger piece.
How much more yarn does a bigger blanket take?
A bigger blanket takes more yarn in proportion to its area, so a blanket 25% wider and 30% longer needs 63% more yarn, not 25%. Multiply the pattern’s yardage by (new width × new length) ÷ (old width × old length), which is exactly what the calculator’s yarn line does for you.
Can I resize by changing yarn instead?
Yes, you can resize by changing yarn instead, and it is the simplest method of all. The same pattern worked in bulky instead of worsted grows by the gauge ratio, roughly 30 to 40%, with no stitch math; check the drape with a swatch first, because a heavier yarn stiffens some stitches.
How much does rounding to the stitch repeat change my width?
Rounding to the stitch repeat changes your width by less than half a repeat, and the calculator shows the real width beside your target. A granny repeat of 3 stitches at 12 stitches per 4 in changes the width by half an inch at most, a difference blocking easily takes up.