Fabric yardage calculator

Fabric is sold by length off a bolt of fixed width, so the question is never "how much area do I need" but "how far down the bolt do my pieces reach when laid side by side". This calculator answers that for one repeated piece: it fits as many as will go across the width, counts the rows, and adds the seam allowance to every edge first. It also asks whether the fabric can be turned, because a nap or a one-way print takes that option away and often costs a good deal more length.

How it is worked out

length = ceil(quantity ÷ pieces across) × piece length, seam allowance included

Pieces across is the fabric width divided by the piece width, rounded down — a fraction of a piece is not a piece. Where the fabric may be turned, the same sum is run with the piece rotated and the cheaper of the two is used. Every measurement must be in the same unit, and the answer comes back in it: centimetres in, centimetres out.

Source: rectangles laid in rows across a fixed width

Questions people ask

Why does the answer change when I say the fabric has a nap?

Because a nap, a pile or a printed picture has an up and a down, so every piece must be cut the same way round. Velvet cut in two directions reads as two different colours under the same light. Losing the freedom to rotate pieces can add a lot of length — in the worked example on this page it takes the requirement from 80 to 120.

Does this handle a whole garment?

It handles one piece at a time, repeated. For a garment, run it once per piece — front, back, sleeve — and add the results, which slightly overestimates because a real cutting layout nests small pieces into the gaps beside large ones. Overestimating fabric is the mistake you can live with.

What is a typical bolt width?

Quilting cotton is usually around 110 cm, dress and shirting fabrics 140 to 150 cm, and home furnishing fabric 137 cm or wider. Measure the piece you are buying rather than trusting the category: the usable width is narrower than the bolt if the selvedge is printed or damaged, and this calculator takes the width you give it.

Is the seam allowance added once or twice?

Twice on each dimension — once for each edge. A 50 by 70 piece with 1.5 of allowance is cut at 53 by 73. If your pattern pieces already include the allowance, set this field to zero rather than adding it again.

What about matching a stripe or a plaid?

Add at least one full repeat of the pattern to the length, and more if the pieces are large. Matching means sliding pieces along the fabric until the lines line up, and that sliding is fabric you have to own. This calculator does not model it, so treat its answer as the floor rather than the figure.

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