Curtain Fabric Quantity: Widths, Cut Drops, Pattern Repeat & Metres to Order

The formula

This is the expression the tool evaluates. Every term is named underneath, with the unit it must be supplied in.

How the result is derived

Step by step, from the values you type to the figure on screen.

1. The 7 inputs are read from the form on every keystroke: Track or Pole Width, Finished Drop, Pairs (or Single Panels) of This Size, Heading Fullness, Usable Fabric Width, Top & Bottom Hem Allowance and Pattern Repeat (0 for a Plain).
2. Each value is checked against the accepted range in the input table below. A value outside its range stops the calculation rather than producing a misleading figure — the results blank out and a message appears.
3. The validated values are substituted into the expression above, which resolves Fabric to Order together with every supporting figure in one pass — no value is carried over from a previous entry.
4. The supporting outputs — Fabric Widths across the Track, Cut Drop, Pattern Repeats per Drop, Extra Fabric for Repeat Matching, Fullness Actually Achieved, Lining to Order (Plain, Same Widths) and Widths per Curtain of a Pair — come from the same pass, so they always describe the same case as the headline figure.
5. Results are rounded for display only. The full-precision value is used throughout the chain, so reading a rounded intermediate figure back into the tool by hand can shift the last digit.

What each input means

Where to read each value on the floor, the unit it must be in, and the range the tool accepts.

What the tool returns

The headline figure and every supporting value it is built from.

Worked example

Substituting

In a plain fabric the same pair takes 10.4 m. The 64 cm repeat costs 2.4 m, nearly a fifth of the order.

How to use it

1. Work through the input groups in order — Window and Make-Up & Fabric. The defaults are a realistic case, so you can change one value at a time and watch what moves.
2. There is no calculate button. Every figure recalculates as you type or drag, which is what makes this usable for a what-if sweep rather than a single answer.
3. Read Fabric to Order in the dark results panel — that is the headline figure, expressed in m.
4. Check the supporting rows underneath (Fabric Widths across the Track, Cut Drop, Pattern Repeats per Drop, Extra Fabric for Repeat Matching, Fullness Actually Achieved, Lining to Order (Plain, Same Widths) and Widths per Curtain of a Pair) before acting on the headline — they are where an implausible input usually shows itself first.
5. Reset to defaults returns every field to the reference case, which is the quickest way to check whether a surprising result came from the tool or from an input you had changed earlier.

Where this is used

• Process planning — establishing Fabric to Order before a trial is booked, so machine time and material in Apparel Manufacturing & Garmenting are committed against a calculated figure rather than an estimate.
• Costing and quotation — Fabric to Order is an input to the cost sheet, and quoting from a worked number rather than a remembered one is what keeps a margin intact.
• Troubleshooting — when the floor result drifts from plan, entering the measured values (starting with Track or Pole Width) shows how much of the gap in Fabric to Order each variable explains.
• Teaching and study — the accepted ranges bracket normal Apparel Manufacturing & Garmenting practice, so moving one variable at a time shows the shape of the relationship rather than a single answer.

Reading the result

Typical bands and what each one is telling you.

Assumptions and limits

• Fullness is the heading's: the tape or pleat style decides how much fabric gathers into each centimetre of track, and the maker of the tape states it. Widths are rounded up to whole widths and the actual fullness shown is what those whole widths give; half widths are common in a pair and are left to the maker. Pattern matching rounds every cut drop up to whole repeats; plains use the hems alone. The lining uses the same widths at the finished drop plus the hems, with no repeat, which suits a lining of similar width. **This is a quantity take-off for ordering; the maker's own allowances for their workroom come first.**
• Every input is bounded to the range normal practice occupies (Track or Pole Width 30 to 2000 cm, Finished Drop 30 to 1000 cm and Pairs (or Single Panels) of This Size 1 to 100 sets, and so on for the rest). Those bounds are guard rails against typing errors, not a claim that the formula fails one unit outside them.
• The calculation is deterministic: the same inputs always give the same result. It carries no allowance for machine condition, operator skill, ambient conditions or lot-to-lot material variation unless an input above explicitly represents one.
• Nothing is sent anywhere. The maths runs in your browser, so the numbers you type never leave the page.

Standards and further reading

• The heading tape maker's fullness ratio for the tape or pleat style chosen.
• EN 13772 and EN 1101, curtain and drape flammability tests, where a contract or public building requires flame-retardant fabric.
• The fabric label: usable width, vertical and horizontal repeat, and any drop direction.

Questions people ask