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输入窗户宽度、褶皱倍数和布幅宽，快速算出一扇窗帘需要几米布，省得买多或买少。
Actual width of your window or curtain rod/track. Measuring the curtain rod length is recommended for accuracy.
The ratio of finished curtain width to window width. A higher ratio creates more fullness. Common ratios are 1.8-2.0x; sheer curtains can go up to 2.5x.
Curtains extend beyond the window on both sides for better light blocking. Enter the total extension for both sides here, typically 20-40 cm.
Fixed-Height Fabric: Fabric has a fixed height (e.g., 2.8 meters). Purchased directly by the finished curtain width; material needed equals curtain width in meters.
Please enter window width, fullness ratio, and other parameters to estimate curtain fabric.
Trigonometry Calculator
Calculate six trigonometric functions from radian values with custom decimal precision.
Inverse Trigonometric Function Calculator
Accurately calculate radian values for inverse trig functions like arcsin and arccos. Supports 6 function types and custom decimal precision.
Least Common Multiple (LCM) Calculator
Quickly calculate the least common multiple (LCM) of two or more integers. Supports space-separated number list input.
Your window is 3 meters wide, you want center-draw curtains with a 1.8x fullness ratio, and your fabric roll is 1.5 meters wide—how many meters of fabric should you buy? With our calculator, just plug in the numbers and get instant results. Whether you're a homeowner remodeling, an interior designer, or a DIY mom prepping your own fabric, this tool saves you from doing the math manually.
There is only one core formula: Total Fabric Length = (Window Width × Fullness Ratio) ÷ Fabric Width × 2 (for center-draw curtains), then rounded up to the nearest meter or half-meter. The fullness ratio is typically 1.5 to 2.5; a higher ratio means denser, richer pleats. Standard fabric widths are usually 1.4m or 1.5m (narrow) and 2.8m (wide). If your window is very wide, you may need to seam fabric cuts together. The calculator automatically accounts for the number of cuts and the length of each.
For example: A 3-meter wide window, 1.8x fullness ratio, 1.5-meter fabric width, making center-draw curtains.
① Single panel coverage width = 3 ÷ 2 = 1.5 meters (each side covers half the window).
② Single panel actual fabric width = 1.5 × 1.8 = 2.7 meters.
③ Number of fabric cuts per side: 2.7 ÷ 1.5 = 1.8, rounded up to 2 cuts (seamed together). Length of each cut = Window height + top/bottom hems (usually 20–30 cm). If the height is 2.7 meters, each cut is 2.9 meters. One side requires 2 cuts × 2.9 meters = 5.8 meters. Total fabric: 5.8 × 2 = 11.6 meters, rounded up to 12 meters. Our calculator directly displays these intermediate numbers and the final recommended purchase length.
Primary Example: A window 3m wide and 2.7m high, using a 1.8x fullness ratio, 1.5m fabric width, center draw.
Action: Enter 3 for "Window Width", 2.7 for "Window Height", 1.8 for "Fullness Ratio", 1.5 for "Fabric Width", and select "Yes" for Center Draw. Click Calculate. The results will show:
Comparison Example: The same window, using wide fabric (2.8m width), 1.8x fullness ratio, center draw.
Action: Change fabric width to 2.8. Result: Number of cuts needed per panel = 2.7 ÷ 2.8 = 0.96 → rounded up to 1 cut. Each panel only needs 1 cut, length = 2.9m, total fabric = 2.9 × 2 = 5.8m, recommended purchase 6 meters. This saves half the fabric length compared to narrow fabric, but you must confirm if the fabric pattern is suitable for wide-width orientation.
