Cast-On & Pattern Repeat Calculator
A stitch repeat decides which widths exist. A 24-stitch lace repeat sizes in 4.8-inch steps — twelve times coarser than a rib.
| Repeats | Cast on | Width | Off by |
|---|
The repeat decides which widths exist
Width times gauge is one multiplication, which is why this sounds like it should not need a page. The part that actually bites is that you cannot cast on the answer. A pattern worked over "a multiple of 8 plus 3" admits only the counts 8k+3, so the widths available to you come in steps of
repeat ÷ stitches per inch
and the worst you can be out is half a step. That is not a rule of thumb — swept across 203,904 combinations of repeat, gauge, balancing stitches, edge stitches and target width, the miss never once exceeds half the granularity, and it reaches exactly that bound. It is tight.
| Stitch repeat | Widths available, every… | Worst miss | |
|---|---|---|---|
| multiple of 2 | 0.40″ | 0.20″ | rib, seed, simple textures |
| multiple of 4 | 0.80″ | 0.40″ | rib, seed, simple textures |
| multiple of 6 | 1.20″ | 0.60″ | most cables and small lace |
| multiple of 8 | 1.60″ | 0.80″ | most cables and small lace |
| multiple of 12 | 2.40″ | 1.20″ | most cables and small lace |
| multiple of 16 | 3.20″ | 1.60″ | large lace and panel motifs |
| multiple of 20 | 4.00″ | 2.00″ | large lace and panel motifs |
| multiple of 24 | 4.80″ | 2.40″ | large lace and panel motifs |
| multiple of 32 | 6.40″ | 3.20″ | large lace and panel motifs |
At 5 stitches to the inch a 2-stitch rib gives you widths 0.4″ apart, and a 24-stitch lace gives you widths 4.8″ apart — twelve times coarser.
Which means lace is the hardest thing to size
That is the part worth carrying away, because it runs opposite to intuition. The more elaborate the stitch pattern, the less control you have over the finished measurement — and lace, where people most want an exact wingspan or an exact width, has the biggest repeats there are. A shawl in a 24-stitch repeat is sized in five-inch steps whether that suits you or not.
There are only three ways out and it is worth knowing which one you are taking. Change the repeat to a smaller one. Add plain stitches at the edges, which buys you single-stitch resolution at the cost of a plain border. Or accept the nearest available width, which is usually fine and is always better than discovering the problem at row 200.
Notes
- The neighbours are shown on purpose. "39.0 or 40.6, pick one" is the real decision. Showing only the nearest would make the tool look more precise than the stitch pattern actually allows.
- Row repeats do the same thing vertically. A 12-row pattern repeat means the lengths available are 12 rows apart, and stopping mid-repeat leaves a visibly unfinished motif at the top edge.
- Edge stitches are not decoration. Most lace and cable patterns behave badly right at the selvedge, and you need something plain to seam into or pick up from. Two or three each side is normal, and they give you finer sizing as a bonus.
- Gauge in pattern, not in stocking stitch. Cables pull in hard and lace opens out, so a stocking-stitch swatch will mislead you about both the width and the number of repeats that fit.
How to use
- Enter the width you want and your gauge in pattern.
- Add the repeat — the "multiple of N plus M" from the pattern.
- Add edge stitches if the pattern has a plain border.
- Pick from the options either side; the exact width may not exist.
Frequently asked questions
How many stitches should I cast on?
Width times your stitch gauge — but then you have to land on a count the stitch pattern allows. A pattern worked over "a multiple of 8 plus 3" admits only the counts 8k+3, so the answer is the nearest one of those, plus any plain edge stitches. That second step is the one that gets skipped and the one that causes the trouble.
Why can I not get the exact width I want?
Because the repeat quantises it. The widths available to you are spaced repeat ÷ stitch gauge apart, and the worst you can miss your target by is half of that. Swept over 203,904 combinations the miss never exceeds half a repeat and does reach exactly that, so the bound is real and tight rather than a rule of thumb.
Does the stitch pattern really affect how precisely I can size something?
Enormously, and the direction surprises people. At 5 stitches to the inch a 2-stitch rib offers widths 0.4 inches apart; a 24-stitch lace offers them 4.8 inches apart. Twelve times coarser. The more elaborate the pattern, the less control you have over the finished measurement.
Why is lace the hardest thing to size?
Because it has the biggest repeats, and it is exactly where people most want an exact width or wingspan. A shawl in a 24-stitch repeat is sized in roughly five-inch steps whether that suits you or not. Nothing fixes it except a smaller repeat, plain edge stitches, or accepting the nearest available size.
What does "multiple of 8 plus 3" mean?
That the pattern needs a whole number of 8-stitch repeats, plus 3 extra stitches to balance it — so the motif starts and ends the same way across the row. Valid counts are 11, 19, 27 and so on. Add any plain edge stitches on top of that.
Do edge stitches help?
Yes, in two ways. They give you something plain to seam into or pick up from, which most lace and cable patterns need because they behave badly right at the selvedge. And because you can add them one at a time, they restore single-stitch sizing resolution to a pattern that otherwise only offers you coarse steps.
What about the length?
A row repeat does the same thing vertically — a 12-row pattern means the lengths available are 12 rows apart, and stopping mid-repeat leaves a visibly unfinished motif at the top. The tool works that out alongside the width.
Should I swatch in the stitch pattern or in stocking stitch?
In the pattern, always. Cables pull in hard and lace opens out, so a stocking-stitch gauge will mislead you about the width and therefore about how many repeats fit. It is the same swatch you need for everything else, so work it in pattern and get all the numbers at once.
Does this send anything anywhere?
No. Everything is calculated in your browser and nothing is stored or uploaded.
🔒 This tool runs entirely in your browser. Nothing you enter is uploaded, logged, or stored.