This calculator answers the single most common question in both knitting and crochet: how much yarn do I actually need? It works two ways, and the difference between them matters.

Two modes, two levels of certainty

Gauge-based mode takes your target area, your gauge (stitches and rows per inch), and your stitch pattern, and estimates yardage using StitchHow's own calibrated model. It's a genuinely useful planning number before you've bought yarn — but it's a model, built from a small set of real reference points, not a physical law. The full derivation, including the reference projects we checked it against, is on the methodology page.

Swatch-weight mode is the accurate path. Make your gauge swatch as normal, then put it on a kitchen scale instead of putting it away — that single weight, plus its area and your ball's own label numbers, is all the calculator needs. There's no constant to trust or distrust here, because nothing is being modeled; your swatch already IS the answer, just not yet scaled up to your project's full size. Prefer this mode every time you have real yarn in hand.

How the gauge-based model works

Enter your target area in square inches (the tool will help you compute this from a garment's dimensions), your gauge, and your stitch pattern. The calculator computes:

Stitch width from your stitches-per-inch
Stitch height from your rows-per-inch
A yarn-per-stitch length, using a constant specific to your stitch pattern (stockinette and single crochet consume noticeably different amounts of yarn per square inch of finished fabric — see the methodology page for the real comparison data behind that)
A base yardage from your total stitch count
An ease/seam/edging allowance, shown as its own separate percentage on top of the base number — this is never folded into the total silently, because how much allowance you actually need depends on your project's seaming and edging, which only you know.

A worked example

Say you're planning a 20 by 60 inch scarf (1,200 square inches) in stockinette stitch, at a worsted-weight gauge of 4.5 stitches and 6 rows per inch. Run through the calculator (the same numbers used here), that comes out to 1,050 yards before allowance, or 1,155 yards with a standard 10% allowance added on top and shown separately. Change nothing but the stitch pattern to 1x1 rib at the same gauge and area, and the base estimate rises to 1,260 yards (1,386 with the same 10% allowance) — rib pulls in and uses more yarn per stitch than plain stockinette, and the calculator reflects that difference directly rather than treating all stitch patterns as interchangeable.

When the estimate will be less reliable

Heavily textured stitch patterns that aren't in our stitch-pattern list (cables, unusual lace repeats, colorwork with long floats) will diverge more from the model than plain stockinette, garter, rib, or the basic crochet stitches it's calibrated against. For those, swatch-weight mode is doubly worth using.

Related tools

If you already know roughly how much of something you need but want to double-check a different kind of material quantity — paint, tile, mulch, lumber — our sister site GetTheAmount runs the same kind of straightforward, show-the-math calculators for home-improvement projects.

Why we show the allowance separately

A lot of yarn calculators fold a "buy extra" margin silently into the headline number, so you can't tell how much of the total is real calculated yardage and how much is padding. That's a trust problem as much as a math problem — you can't audit a number you can't see the parts of. This tool always shows the base estimate, the allowance percentage, and the allowance yardage as three separate figures adding up to the total, so you can decide for yourself whether 10% is enough margin for a project with heavy seaming, or whether you'd rather push it to 15-20% for something with a lot of finishing work.

Metric or imperial, your choice

Every result is shown in both yards and metres, computed from the same underlying calculation rather than a separate, potentially inconsistent conversion — a project estimated at 1,155 yards will always show as almost exactly 1,056 metres, using the standard 0.9144 metres-per-yard conversion, not an approximation that could drift from the yardage figure over multiple calculations.

FAQ

What if I don't know my gauge yet? Knit or crochet a swatch first — at least 4x4 inches, ideally 6x6 for a more stable measurement — and count your stitches and rows per inch from that. The gauge reference section walks through swatching in more detail.

Does the calculator account for cast-on and bind-off? The base model estimates the working fabric itself. Cast-on and bind-off use comparatively little yarn against the body of a project, and are best covered by the allowance percentage rather than modeled separately.

Can I use this for colorwork? Only roughly. Stranded colorwork carries two strands per row and uses meaningfully more yarn than either color would alone; the swatch-weight mode, using an actual colorwork swatch, will be far more accurate than the gauge-based model for this case.

Yarn Quantity Estimator