Amigurumi Increase Calculator (Magic Ring)
Amigurumi starts with 6 single crochet in a magic ring and adds 6 every round — 6, 12, 18, 24, always multiples of the starting count. A 30 cm circumference at 25 stitches per 10 cm needs 75 stitches, which is 30 ÷ π = 9.5 cm across, and 75 ÷ 6 rounds up to 13 increase rounds. You cannot work half a round, so you land on 78 stitches and the circumference creeps up to 31.2 cm. Start with 8 instead and you increase 8 per round, reaching 80 stitches in 10 rounds with a flatter base.
Your numbers
Increase rounds
13rnds
Stitches
78sts
Diameter
9.5cm
Formula
Stitches = Finished circumference × Stitches per 10 cm ÷ 10, Increase rounds = ⌈Stitches ÷ Starting stitches⌉
The rule is that the increases per round equal the starting count. Start with 6 and increase 8 a round and the circle passes flat and ruffles; increase only 4 and it curls into a bowl instead of lying open. Amigurumi gauge is far tighter than garment gauge, because the hook is deliberately 1–1.5 sizes smaller than the yarn asks for so the stuffing cannot show through. Feeding the gauge printed on the yarn band into this will give you a much bigger toy than you wanted.
What to enter
| Input | Default | Accepted range |
|---|---|---|
| Finished circumference (cm)The garment measured flat and unstretched, right round — not the body it fits. | 30 | 0 and up |
| Stitches per 10 cm (sts/10 cm)Stitches in 10 cm. If you measured over 5 cm, double it before entering. | 25 | 0 and up |
| Starting stitches (sts)The stitch count before shaping. | 6 | 1 ~ 12 |
Step by step
Quick reference table
Results when only Finished circumference (cm) changes and everything else stays put.
| Finished circumference (cm) | Increase rounds (rnds) | Stitches (sts) | Diameter (cm) |
|---|---|---|---|
| 15 | 7 | 42 | 4.8 |
| 22.5 | 10 | 60 | 7.2 |
| 30 | 13 | 78 | 9.5 |
| 45 | 19 | 114 | 14.3 |
| 60 | 25 | 150 | 19.1 |
What each result means
| Result | At default values |
|---|---|
| Increase rounds (rnds)Rounds of increasing to reach the target, adding the starting count each round. | 13 |
| Stitches (sts)Stitch count, measured across. | 78 |
| Diameter (cm)The longest line across a circle — twice the radius. | 9.5 |
Common mistakes
The rule is that the increases per round equal the starting count. Start with 6 and increase 8 a round and the circle passes flat and ruffles; increase only 4 and it curls into a bowl instead of lying open. Amigurumi gauge is far tighter than garment gauge, because the hook is deliberately 1–1.5 sizes smaller than the yarn asks for so the stuffing cannot show through. Feeding the gauge printed on the yarn band into this will give you a much bigger toy than you wanted.
Glossary
- Finished circumference
- The garment measured flat and unstretched, right round — not the body it fits.
- Stitches per 10 cm
- Stitches in 10 cm. If you measured over 5 cm, double it before entering.
- Starting stitches
- The stitch count before shaping.
- Increase rounds
- Rounds of increasing to reach the target, adding the starting count each round.
- Stitches
- Stitch count, measured across.
- Diameter
- The longest line across a circle — twice the radius.
Frequently asked questions
Q. How is Amigurumi Increase Calculator (Magic Ring) calculated?
Stitches = Finished circumference × Stitches per 10 cm ÷ 10, Increase rounds = ⌈Stitches ÷ Starting stitches⌉ — Amigurumi starts with 6 single crochet in a magic ring and adds 6 every round — 6, 12, 18, 24, always multiples of the starting count. A 30 cm circumference at 25 stitches per 10 cm needs 75 stitches, which is 30 ÷ π = 9.5 cm across, and 75 ÷ 6 rounds up to 13 increase rounds. You cannot work half a round, so you land on 78 stitches and the circumference creeps up to 31.2 cm. Start with 8 instead and you increase 8 per round, reaching 80 stitches in 10 rounds with a flatter base.
Q. Can you walk through an example?
With Finished circumference 30cm, Stitches per 10 cm 25sts/10 cm, Starting stitches 6sts, the answer is Increase rounds 13rnds.
Q. What do I need to enter?
Enter Finished circumference, Stitches per 10 cm, Starting stitches. 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 Finished circumference (cm) moves the answer to Finished circumference (cm) 15 → Increase rounds (rnds) 7 and Finished circumference (cm) 60 → Increase rounds (rnds) 25. 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?
The rule is that the increases per round equal the starting count. Start with 6 and increase 8 a round and the circle passes flat and ruffles; increase only 4 and it curls into a bowl instead of lying open. Amigurumi gauge is far tighter than garment gauge, because the hook is deliberately 1–1.5 sizes smaller than the yarn asks for so the stuffing cannot show through. Feeding the gauge printed on the yarn band into this will give you a much bigger toy than you wanted.
Related calculators
Materials differ in density and absorption. If your label states a figure, use it — the defaults here are only common values.