Methods & worked examples
Crochet Starting Chain Calculator — Methods & worked examples
How it works
Measure complete central repeats in a finished, appropriately blocked swatch, excluding edges. A stretched starting chain is not the finished width. Repeat width = measured swatch width ÷ complete repeats. Compare floor and ceil of (target width − combined edge width) ÷ repeat width. Starting chains = m × repeats + a, exactly as your pattern specifies.
Worked examples
Four complete repeats measuring 18 cm give 4.5 cm per repeat. For a 92 cm total target with 3 cm of combined edges, the central target is 89 cm, or about 19.78 repeats. Nineteen repeats yield 88.5 cm total; 20 yield 93 cm. With a 6k + 2 starting-chain rule, the options are 116 and 122 chains.
Scope & limitations
The additional-chain constant a must include whatever the original pattern includes; do not add turning chains twice. The constant is not itself an edge width: measure or specify that separately. Yarn, hook, tension and finishing affect gauge. This tool applies to flat, constant-width repeats, not shaping, increases, decreases, sleeves or garment fit. Estimated widths cannot guarantee identical tension.
Method sources
Our original explanations and calculators use the methods above. This site is not affiliated with the cited brands or organizations.