Blanket Cast-On Calculator 🛏️
Instant and accurate. No sign-up required. Calculate cast-on stitches (knitting) or starting chain (crochet) for a blanket at any target dimensions using your gauge.
How to Use the Blanket Cast-On Calculator
- Start by deciding the finished width and height you want, in either centimetres or inches, and have those numbers ready before you touch the yarn. - Then work a generous swatch, at least 15 cm (6 in) square, in the exact stitch pattern, yarn, and needle or hook you will use, because borders and textured stitches change gauge noticeably. - Wash and block the swatch the same way you will treat the finished blanket, let it dry fully, then measure stitch gauge across the centre and row gauge vertically, ignoring the curled edges. - Enter both gauges plus your target dimensions. - Stitch gauge sets the cast-on or starting-chain count that controls width; row gauge tells you how many rows or rounds reach your target height, which matters for planning yarn and stripe placement. - If a separate border is worked later, calculate the centre panel slightly narrower so the finished piece, border included, lands on your goal dimensions.
- The core formula is: stitches per unit = swatch stitches divided by swatch width, then cast-on = target width times stitches per unit. - Worked example: your blocked swatch shows 16 stitches over 10 cm, so 16 / 10 = 1.6 stitches per cm; a 120 cm wide blanket needs 1.6 x 120 = 192 stitches. - Rows use the same logic with row gauge: 20 rows over 10 cm = 2 rows per cm, so a 150 cm length needs 2 x 150 = 300 rows. - In imperial, 18 sts over 4 in = 4.5 sts/in; a 48 in width needs 4.5 x 48 = 216 stitches. - For crochet the calculator adds the turning chain automatically, 1 extra for single crochet, 2 for half-double, 3 for double, so a 192-stitch double-crochet blanket starts from a chain of 195. - Always round to whatever stitch-multiple your pattern repeat requires, rounding up so the blanket never finishes narrower than planned.
- Accuracy compounds across a blanket's width, so small gauge errors get magnified more than on small projects. - Being off by just one stitch per 10 cm on a 120 cm blanket shifts the count by roughly 12 stitches and the finished width by several centimetres, and the same drift across hundreds of rows can waste or leave you short on yarn. - The most common mistake is measuring an unblocked swatch: many fibres, especially wool and cotton, relax and grow after washing, so an unwashed measurement overstates stitches per centimetre and produces a blanket that ends up too wide and too hungry for yarn. - Measure over the largest span possible and average two or three readings. - Hold the fabric flat without stretching, and pin a blocked swatch to true dimensions before measuring. - Following the Craft Yarn Council standard yarn weight system when choosing needle or hook size gives a sensible starting gauge, but your own blocked swatch always governs the final count.
FAQ
How wide should I cast on for a blanket?
Divide your target width by your gauge swatch width, then multiply by the number of stitches in your gauge swatch. This calculator does that math automatically.
How many chains do I start with for a crochet blanket?
For a single crochet blanket, add 1 turning chain to your stitch count. For double crochet, add 3. This calculator automatically includes the correct turning chain.
Does gauge matter for a blanket?
Yes — gauge determines the finished dimensions. A difference of even one stitch per 10 cm across a 120 cm blanket adds or removes about 12 stitches, affecting finished width by several centimetres.
Should I swatch for a blanket?
Swatching is recommended even for blankets, especially if you want a specific finished size. Wash and block your swatch before measuring for the most accurate gauge.