Window width × 2 to 2.5 (for fullness) × number of panels for the total fabric width. Then multiply the drop length by the number of widths needed, and add 30 cm for hems and headers. Use the calculator above with piece length = drop + 30 cm and piece width = window width × fullness.

Add 10–25%. Napped fabrics like velvet and corduroy must have all pieces oriented the same way, which uses more length. Plaids and stripes need extra so you can match patterns at seams. One-way prints (animals, text, scenes) need a single orientation too.

For cotton, linen, denim and wool, yes — they shrink, and shrinking after sewing is heartbreaking. Pre-wash the fabric the same way you'll wash the finished garment. If you don't pre-wash, use the higher end of the shrinkage estimate above so you don't run short.

A quilting term: 18 × 22″ (≈46 × 56 cm). It's a half-yard cut from quilting cotton (~110 cm wide), then halved across the width — giving a square-ish piece more useful than the long thin "skinny quarter".

This calculator assumes you're cutting multiple identical rectangles. A pattern envelope's number is based on the actual layout of all the differently-shaped pieces nested together — work the calculator can't replicate. For full garments, use the Garment fabric estimator or trust the pattern envelope.

Older patterns and US patterns use imperial inches; European patterns use metric. Many modern patterns include both, which means you'll regularly need to convert between them when following directions or comparing pattern envelopes.

Yes — 1 inch is exactly 2.54 cm by international agreement. The calculator shows two decimal places, which is well below the cutting precision of any home sewist (a sharp pair of shears is accurate to about 1 mm).

Yes — that's the standard rounding used on commercial patterns. The exact value is 1.59 cm, so the difference is under 1 mm and well within fabric stretch and cutting variance. The same applies to 1/4″ ≈ 6 mm (exact 6.35 mm) and 3/8″ ≈ 1 cm (exact 9.5 mm).

Type either 1 1/2 with a space, or 1-1/2 with a hyphen — both work. You can also use a decimal (1.5) or just the fraction (3/2). The calculator parses any of these.

Bias-cut strips stretch and curve. Straight-grain binding only works on perfectly straight edges — try it on a curved hem or armhole and you'll see it bunch up. Anywhere there's a curve, bias is the right choice.

About 5–10%, mostly in the corners. It's one of the more efficient methods — far better than cutting individual strips and joining them, which can waste 20–30% in seam allowances.

Yes — common widths are 1.3 cm (single fold) and 6 mm (double fold finished). Pre-made saves time but limits your colour, fibre, and pattern choices, and is usually polyester rather than the same fabric as your garment.

Always. Necklines and armholes are curved — bias hugs them. A 2.5–3 cm cut strip yields a 6 mm finished double-fold bias binding, the standard for clean inside finishes on curves.

Pattern designers do "marker making" — fitting all the differently-shaped pieces together onto the fabric like a jigsaw. The bodice tucks into the curve under the sleeve, sleeves nest into the skirt's spare width. A calculator can only approximate by treating each piece as a rectangle.

Tick the plus-size box for ~15% more. For very large sizes (UK 24+), add another 0.25–0.5 m to be safe — pieces grow in both length and width, but width grows faster than the calculator's linear adjustment captures.

Use the special-fabric dropdown. Napped fabrics (velvet, corduroy, fleece) have a direction — the pile catches light differently end-to-end — so all pieces must be cut facing the same way. That uses more length than a non-napped layout.

Pick "plaid / striped" — adds 25%. Matching plaid at seams means cutting each piece so its plaid lines up with the next one, which forces you to cut every piece individually rather than from folded fabric, and waste fabric to align repeats.

The bases are for adults. As a starting point, halve the estimate for primary-school age and add a little. For a child's full-skirted dress at 150 cm wide, expect around 1.5–2 m rather than the 4 m the adult estimator returns.

Button diameter plus 3 mm (1/8″) for ease. For thick or domed buttons, add another 2–3 mm so the buttonhole isn't strained around the button's profile.

On a shirt placket, 1.5–2 cm below the collar stand. On a dress front, 5–7 cm below the neckline finish so the neckline doesn't gape. The calculator above lets you set this directly with the "top button from top edge" field.

It's a hangover from when wealthy women's clothes were buttoned by maids. Maids stood facing the wearer, so buttons on the wearer's left were on the maid's right — the side of their dominant hand. Most pattern designers still follow the convention.

Horizontal for plackets and waistbands (the button slides to the corner under stress, holding firm). Vertical for narrow plackets and shirt fronts where there's less side-to-side strain. The calculator's spacing works for either orientation.

Every 6–8 hours of active sewing, or at the start of any project where stitch quality matters. A dull needle is the #1 cause of skipped stitches, snagging, and pulled threads — and changing one is a 30-second job.

Universal has a slightly rounded point that handles most wovens fine. Microtex (sometimes labelled "Sharp") has a very fine, sharp point — better for densely-woven fabrics like silk, microfibre, oilskin, and high-thread-count cottons where a Universal might deflect.

You can on the body of the garment, but you'll likely break it on thick seam intersections. Jeans needles have a stronger shaft and a sharper point designed for denim. Use one whenever you're crossing more than three layers of medium fabric.

Ballpoint or Stretch — they have a rounded tip that slips between the yarns rather than piercing them, preventing skipped stitches and pulled runs in the knit. Stretch needles also have a special "scarf" that helps the bobbin thread catch reliably on stretchy fabric.

Schmetz Universal 80/12 — sews 90% of dressmaking fabrics adequately. Pair it with a Stretch 75/11 for knits and a Jeans 100/16 for denim and you'll cover almost everything.

Polyester sew-all — Gütermann's is the most widely-stocked in the UK. It's strong, doesn't shrink, works on virtually anything from chiffon to denim, and comes in hundreds of colours. A small starter set covers most projects.

For most sewing, yes — same fibre, same weight, same colour. Mismatching causes tension issues. Exceptions: very fine fabrics (use a finer bobbin to reduce seam bulk), and heavy topstitching (use a regular thread in the bobbin since topstitch thread doesn't always run smoothly in a bobbin case).

30 wt or 40 wt thread (Gütermann's "Topstitch" or "Jeans" lines), with a topstitching needle (size 100/16) and a longer stitch length (3–3.5 mm). The chunkier thread is what gives that classic visible "denim look".

Cotton on cotton is traditional and behaves more naturally as the quilt is washed and aged. Polyester is fine and stronger but doesn't shrink with the fabric, so heirloom quilters generally prefer cotton. For piecing, 50 wt cotton (Aurifil, Mettler Silk-Finish) is the go-to.

Yes — sergers run through 4 spools at once, so use the larger 2,500–5,000 m cones rather than the 100 m sewing-machine spools. Polyester sew-all weight is fine; some sergers prefer specifically labelled "overlocker thread", which is slightly thinner and runs more smoothly through the loopers.

Three usual suspects: tension is too tight, stitch is too short for the fabric, or thread is too thick for the fabric. Try lengthening the stitch first (try 3 mm), then loosening upper tension by half a number. A fresh needle and the right needle type also help.

3–3.5 mm with topstitching thread and a Jeans needle (size 100/16). The slightly longer stitch shows the topstitch thread better and gives jeans their characteristic visible-stitching look. Use a regular sew-all in the bobbin.

Stretchy fabrics (a tight straight stitch will pop when the fabric stretches), edge finishing on woven fabrics (raw edges fray less), applique, buttonholes, and decorative work. For knit construction, a narrow zigzag (~1 mm wide × 2.5 mm long) is the standard choice on a regular sewing machine.

Basting is a long temporary stitch (4–5 mm) that you remove after the final seam is sewn. Use it to hold pieces in place before final stitching, especially curved or fitted seams. Loose-tension basting is also how you create even gathers — pull the bobbin thread to draw up the fabric.

Almost always a needle problem — dull, bent, or the wrong type for the fabric. Change the needle first. If that doesn't fix it, check that the needle is fully inserted and the right way round (flat side of the shank to the back on most home machines).

"Do not" — e.g., a crossed-out tub means do not wash, a crossed-out triangle means do not bleach, a crossed-out iron means do not iron. The cross is a strict prohibition; the garment will likely be damaged if you ignore it.

Hand wash is gentler. If your garment shows a "hand in tub" symbol, hand wash is safest, but most modern machines have a "hand wash" or "delicates" cycle that approximates hand-washing — short, gentle agitation, low spin speed, cool water.

One dot = low (max 60 °C), two dots = medium (max 80 °C), three dots = high (max 95 °C). Crossed-out circle-in-square = do not tumble dry. The dots system is the same for ironing — one dot is synthetics, two is wool/silk, three is cotton/linen.

The American ASTM symbols are very similar to ISO 3758 but use letters in some cases (e.g., "W" or "P" inside a circle for solvent type for dry cleaning). Garments sold internationally usually carry both, or the system that applies in the country of sale.

It means "gentle" — one line under a tub means gentle wash cycle; two lines means very gentle / delicate. Same convention applies to tumble drying.