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Chain to Length Calculator

163 chains worked at 20 chains per 10 cm measure 81.5 cm. Work the first row into them at 16 stitches per 10 cm and that row wants 101.9 cm — a gap of 20.4 cm. The chain has to stretch by that much for the row to lie flat, so the bottom edge ends up taut and the fabric widens as it grows: a trapezoid, not a rectangle.

Your numbers

Chain length

81.5cm

Finished width

101.9cm

Difference

20.4cm

Formula

Chain length = Chain stitches ÷ Chains per 10 cm × 10, Finished width = Chain stitches ÷ Stitches per 10 cm × 10

This is the most common failure in crochet, and measuring the chain against a ruler will never catch it, because you stretch it while you measure. Chain twenty, let go, and measure it relaxed. If the gap is big, chain with a hook one or two sizes larger, or skip the chain and use a foundation row (fsc, fdc) that makes the chain and the first row together — the base then comes out at row gauge and this calculation stops mattering. A negative gap means the chain is looser than the row, and the bottom edge will ripple instead.

What to enter

InputDefaultAccepted range
Chain stitches (sts)How many chains you make to start, turning chain included.1630 and up
Chains per 10 cm (sts/10 cm)Chains per 10 cm of relaxed chain — never measure it stretched.200 and up
Stitches per 10 cm (sts/10 cm)Stitches in 10 cm. If you measured over 5 cm, double it before entering.160 and up

Step by step

FormulaChain length = Chain stitches ÷ Chains per 10 cm × 10, Finished width = Chain stitches ÷ Stitches per 10 cm × 10
With the default numbersChain length = 163 ÷ 20 × 10, Finished width = 163 ÷ 16 × 10
AnswerChain length = 81.5 cm

Quick reference table

Results when only Chain stitches (sts) changes and everything else stays put.

Chain stitches (sts)Chain length (cm)Finished width (cm)Difference (cm)
81.540.850.910.2
1226176.315.3
16381.5101.920.4
245122.5153.130.6
326163203.840.8

What each result means

ResultAt default values
Chain length (cm)The length that chain measures when it is not being pulled.81.5
Finished width (cm)The width when finished, before any seam or fold allowance.101.9
Difference (cm)The gap between two values — a quantity, not a rate.20.4

Common mistakes

This is the most common failure in crochet, and measuring the chain against a ruler will never catch it, because you stretch it while you measure. Chain twenty, let go, and measure it relaxed. If the gap is big, chain with a hook one or two sizes larger, or skip the chain and use a foundation row (fsc, fdc) that makes the chain and the first row together — the base then comes out at row gauge and this calculation stops mattering. A negative gap means the chain is looser than the row, and the bottom edge will ripple instead.

Glossary

Chain stitches
How many chains you make to start, turning chain included.
Chains per 10 cm
Chains per 10 cm of relaxed chain — never measure it stretched.
Stitches per 10 cm
Stitches in 10 cm. If you measured over 5 cm, double it before entering.
Chain length
The length that chain measures when it is not being pulled.
Finished width
The width when finished, before any seam or fold allowance.
Difference
The gap between two values — a quantity, not a rate.

Frequently asked questions

Q. How is Chain to Length Calculator calculated?

Chain length = Chain stitches ÷ Chains per 10 cm × 10, Finished width = Chain stitches ÷ Stitches per 10 cm × 10 — 163 chains worked at 20 chains per 10 cm measure 81.5 cm. Work the first row into them at 16 stitches per 10 cm and that row wants 101.9 cm — a gap of 20.4 cm. The chain has to stretch by that much for the row to lie flat, so the bottom edge ends up taut and the fabric widens as it grows: a trapezoid, not a rectangle.

Q. Can you walk through an example?

With Chain stitches 163sts, Chains per 10 cm 20sts/10 cm, Stitches per 10 cm 16sts/10 cm, the answer is Chain length 81.5cm.

Q. What do I need to enter?

Enter Chain stitches, Chains per 10 cm, Stitches per 10 cm. The result recalculates as you type, and an empty box counts as zero.

Q. How much does the answer move if I change a number?

Changing only Chain stitches (sts) moves the answer to Chain stitches (sts) 81.5 → Chain length (cm) 40.8 and Chain stitches (sts) 326 → Chain length (cm) 163. The table below lays out five steps.

Q. How are the numbers rounded?

Money is shown to the nearest whole unit, percentages to one decimal place and everything else to two. What you see is rounded; the calculation itself carries the unrounded value forward.

Q. Anything to watch out for?

This is the most common failure in crochet, and measuring the chain against a ruler will never catch it, because you stretch it while you measure. Chain twenty, let go, and measure it relaxed. If the gap is big, chain with a hook one or two sizes larger, or skip the chain and use a foundation row (fsc, fdc) that makes the chain and the first row together — the base then comes out at row gauge and this calculation stops mattering. A negative gap means the chain is looser than the row, and the bottom edge will ripple instead.

Related calculators

Materials differ in density and absorption. If your label states a figure, use it — the defaults here are only common values.