THE METHOD BEHIND THE COUNT
One rail.
Two ways to buy.
Curtaincount separates finished curtain panels from fabric cut off a roll. Both models start with the same rail width and a fullness multiplier you choose, but they produce different shopping quantities.
The shared starting point
Enter rail or track width in metres and the desired finished drop in centimetres. The width used here is the rail width you intend to cover, rather than an assumed window width.
The fullness multiplier expresses target total flat curtain width as a multiple of rail width. For example, a hypothetical 2.4 m rail and a chosen multiplier of 1.8 give a 432 cm target flat width. These numbers illustrate the method; 1.8 is not a recommendation.
Target flat width (cm) = rail width (cm) × chosen fullness
Ready-made panels: width first, then packs
Use the finished flat width of one individual panel, before gathering. A product sold as a pair might list individual panel width or the combined pair width; confirm which quantity the label gives before entering it.
The minimum panel count is the target total flat width divided by individual panel width, rounded up. A separate panels-per-pack input then rounds that count into whole purchased packs. The quoted cost is per pack, so a pair's price does not accidentally become the price of one panel.
Packs to buy = round up (panels needed ÷ panels per pack)
Panels supplied = packs × panels per pack
Suppose the target width is 400 cm and each hypothetical panel is 150 cm wide. The arithmetic requires three panels. If the product is sold only in pairs, enter two panels per pack: two packs supply four panels. Those four panels' combined flat width is 600 cm, so the purchased quantity exceeds the target.
The result shows fullness implied by the purchased flat width as well as the target fullness. Whole-panel and pack rounding can make these different.
Ready-made drop comparison
The desired finished drop is your chosen measurement. If you enter the product's listed finished drop, Curtaincount shows the centimetre difference. A positive difference means the listed product is longer; a negative difference means it is shorter.
This comparison does not alter the product or calculate alteration costs. The calculator does not determine the mounting position, heading compatibility or whether a particular finished panel will fit your design. With the product drop blank, only the width and pack count are checked.
Fabric by the metre: whole widths and cut lengths
Fabric mode treats every full-width drop as one rectangular piece cut from the roll. The raw roll width loses the allowance you enter at each side. That side allowance is subtracted twice from every width—whether your plan uses it for seams or side hems.
The calculator rounds up the number of usable fabric widths needed to cover the target flat width. Each width's cut length is the desired finished drop plus your top and bottom allowances. It multiplies the number of widths by that cut length to get linear metres of fabric.
Whole drops = round up (target flat width ÷ usable width)
Cut length (cm) = finished drop + top + bottom allowance
Fabric (linear m) = whole drops × cut length ÷ 100
Fabric drops are not necessarily finished curtain panels. Several widths may be joined into a finished curtain, and the sewing plan decides how those widths are distributed. This model does not optimise joining layouts or make use of offcuts across different curtains.
A fabric example from start to finish
Every figure below is hypothetical, including the multiplier and allowances.
| Input or result | Illustrative quantity |
|---|---|
| Rail width and chosen fullness | 2.4 m × 1.8 |
| Target total flat width | 432 cm |
| Roll width and allowance per side | 150 cm and 2 cm |
| Usable width per drop | 150 − 2 × 2 = 146 cm |
| Whole drops | Round up 432 ÷ 146 = 3 |
| Finished drop, top and bottom allowance | 220 + 10 + 20 cm |
| Cut length per drop | 250 cm |
| Fabric before purchasing rounding | 3 × 250 ÷ 100 = 7.5 linear m |
Purchasing increments and cost
Fabric purchasing increments are optional. With 0 entered, the result uses the exact calculated linear metres. If your shop supplies fabric in a particular increment, enter that real increment and the calculator rounds the total length up to the next multiple. It does not apply a minimum order.
A hypothetical 7.5 m requirement and a 1 m purchasing increment produce 8 m to buy, leaving 0.5 m above the calculated cut lengths. The quote uses 8 m, rather than 7.5 m.
Fabric cost = purchased linear metres × price per linear metre + delivery
Delivery is added once per order. Price is optional; leaving it blank produces a quantity-only plan. A price of zero is treated as an entered quote of zero. Quotes are used as entered and totals are rounded to cents; include GST in the input if that is how you want to compare a quote.
What needs a separate plan
Pattern-repeat alignment, fabric shrinkage, lining, heading supplies, joins beyond the side allowances entered, product availability and alteration costs are outside these formulas. The tool does not suggest any allowance for them.
Verify the product's width and drop conventions and use a sewing or product plan suitable for what you intend to buy. Curtaincount makes the arithmetic visible; it does not specify a curtain design.