What this planner works out
This planner converts blanket dimensions and gauge into a cast-on stitch count and row count, and estimates the yarn from the area.
Presets cover the standard sizes, which are worth starting from — a blanket that does not match a bed size looks wrong however well it is made.
Blanket details
Before you start
- Choose the size for the use. A lap blanket and a bed throw have different proportions, and a bed throw needs to overhang.
- Gauge must come from a swatch in the actual stitch pattern, blocked as the finished blanket will be.
- The metres per 100 cm² figure also comes from the swatch. It varies enormously between stitch patterns.
- Blankets are large, so gauge errors compound. A 5% error on a 200 cm blanket is 10 cm.
A 5% gauge error on a scarf is 1 cm and invisible. The same error on a 200 cm blanket is 10 cm, and on the yarn requirement it is 10% — which on a large project can be several balls. Blankets are the projects where swatching pays for itself most clearly, and the ones where knitters most often skip it because there is no fit to worry about.
How this calculator works
Dimensions divided by gauge, area times a rate:
Cast-on = width ÷ 10 × stitches per 10 cm
Rows = length ÷ 10 × rows per 10 cm
Yarn = width × length ÷ 100 × metres per 100 cm²The stitch and row counts are rounded to whole numbers. For a stitch pattern with a repeat, the cast-on should be adjusted to a multiple of the repeat plus any edge stitches, which will move the finished width slightly.
Worked example: a baby blanket
Using the default figures — 90 by 90 cm at 18 stitches and 24 rows to 10 cm, 3.5 m per 100 cm²:
- Cast on: 162 stitches
- Rows: 216
- Area: 0.81 m²
- Yarn: about 284 m
Scale to a single bed throw at 135 by 200 cm and the same gauge gives 243 stitches, 480 rows and 945 m of yarn — more than three times the baby blanket for a project that sounds only somewhat larger. Area scales with both dimensions, which is why blanket projects expand so much faster than their measurements suggest.
Common mistakes
- Not swatching because there is no fit to worry about. Size and yardage both depend on gauge.
- Ignoring the stitch pattern repeat. The cast-on must accommodate it.
- Underestimating how yarn scales. Area rises with both dimensions.
- Forgetting the border. An edging adds both yarn and finished size.
- Choosing a non-standard size for a bed. It will look wrong on the bed.
Frequently asked questions
What size should a blanket be?
Common UK figures are around 70 by 90 cm for a pram blanket, 90 by 90 for a baby blanket, 100 by 120 for a lap blanket, and bed throws sized to overhang the mattress — roughly 135 by 200 for a single and 200 by 200 for a double. For a bed, measuring the actual mattress and adding the desired overhang is more reliable than a standard figure.
How do I stop the edges curling?
Stocking stitch curls by nature. A garter stitch, seed stitch or ribbed border of several centimetres holds it flat, as does a crocheted edging. The border needs planning into the stitch count from the start, since adding one afterwards changes the finished dimensions.
Should I knit a blanket in one piece or in squares?
One piece avoids seaming and gives a cleaner result; squares are portable, use up leftovers and let you stop and start. A large one-piece blanket becomes heavy and awkward on the needles well before it is finished, which is a practical argument for panels or squares on anything bed-sized.
What yarn suits a blanket?
Something washable and hard-wearing, since blankets are used and laundered. Superwash wool, cotton and good acrylic all work. Weight matters more than for a garment — a blanket in aran or chunky yarn grows faster and is warmer, while 4-ply produces a lighter, finer result over considerably more time.
Is what I enter stored?
No. Figures are processed in your browser and never transmitted or retained.
Related tools
References
- GOV.UK — textile safety, labelling and standards for items for children
- MoneyHelper — budgeting for craft projects
Sources are checked at publication and can change — how I choose and check references.