Crochet Blanket Size & Starting Chain Calculator

How to calculate

1. Measure interior fabric with the same yarn, hook, stitch pattern and finishing. Enter whole stitches and their measured span, not loose chain length.
2. Working count = M × whole repeats + E, with at least one repeat. E is the total additional worked edge count; do not reduce it modulo M. Rows use Q × repeats + F.
3. Only use a known rule: starting chains = working stitches + extra chains. Include all skipped or turning chains exactly once. A “multiple plus” chain instruction does not define worked edge stitches.
4. Compare the two neighboring repeat-compatible counts. “At least” chooses the upper option; “closest” can choose a smaller one and chooses fewer stitches in an exact tie. Width and length are selected independently.
5. Count completed rows consistently with your swatch. Foundation chains are not extra rows.

What the calculator shows

• Working count = M × whole repeats + E, with at least one repeat. E is the total additional worked edge count; do not reduce it modulo M. Rows use Q × repeats + F.
• Only use a known rule: starting chains = working stitches + extra chains. Include all skipped or turning chains exactly once. A “multiple plus” chain instruction does not define worked edge stitches.
• Count completed rows consistently with your swatch. Foundation chains are not extra rows.
• This is your approximate border allowance on each side. It does not predict border rounds, corners or border gauge.

When to use it

• Resize a flat rectangular blanket.
• Plan a rectangular scarf or panel.
• Check the dimensions of an existing working stitch count.

Gauge and starting-chain guide

Measure interior fabric with the same yarn, hook, stitch pattern and finishing. Enter whole stitches and their measured span, not loose chain length.

Only use a known rule: starting chains = working stitches + extra chains. Include all skipped or turning chains exactly once. A “multiple plus” chain instruction does not define worked edge stitches.

US single crochet and UK double crochet mean the same stitch. In the fictional example, work into the second chain: 10 working stitches need 11 chains. For US double crochet with the skipped three-chain start counted as the first working stitch, 10 total working stitches need 12 chains (extra 2). If that start is not counted, extra 3 may be required. Follow your pattern.

Compare the two neighboring repeat-compatible counts. “At least” chooses the upper option; “closest” can choose a smaller one and chooses fewer stitches in an exact tie. Width and length are selected independently.

Converted text is rounded to six decimals; unchanged measurements retain their exact value. Editing the converted text creates a new measurement. 1 inch = 2.54 cm exactly.

Worked examples

At 20 stitches and 25 rows per 10 cm, a 100 × 150 cm body needs 200 working stitches, 201 starting chains with extra 1, and 375 rows.

At 18 stitches per 10 cm with M=12 and E=2, a 100 cm target has nearby choices of 170 stitches (about 94.444444 cm) and 182 (about 101.111111 cm). With extra 1, use 171 or 183 chains. A 5 cm border per edge around a 100 × 150 cm plain example leaves a 90 × 140 cm body: 180 stitches, 181 chains and 350 rows.

Limits of the estimate

An estimate from your swatch, not a crochet pattern or guaranteed size. Tension, washing and blocking can change the finished dimensions. For flat rectangles only.

Starting chains not calculated: check your pattern’s first-row rule.

This is your approximate border allowance on each side. It does not predict border rounds, corners or border gauge.

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