How to use this calculator
Measure the window, choose how the curtains or drapes should hang, and enter the rod placement you plan to use. The calculator estimates rod width, total fabric width, a ready-made panel size, and a copyable shopping note.
Measurements and units
- Units: Use inches or centimeters. If you switch units, the calculator converts the current measurement values so the preview and shopping note stay in a realistic range.
- Window width: Measure the glass or trim from left to right. This must be greater than zero because it is the base width used to size the rod and curtain fullness.
- Window height: Measure from the top of the window opening or trim to the sill or lower trim. This must be greater than zero and is used when the calculator estimates length without a rod-to-floor measurement.
Panel and fullness choices
- Panel count: Choose how many separate curtain or drapery panels you want to buy. Two panels is common for a standard window, one panel can work for a narrow side draw, and four panels can help cover wide rods with ready-made sizes.
- Fullness: Fullness is the total fabric width compared with the rod width. Use 1x for a flat look, 1.5x for light gathers, 2x for a standard gathered look, and 2.5x for sheers or a fuller drape.
Hanging style and rod placement
- Hanging style: Sill curtains stop around the sill, below-sill curtains add a short drop below it, floor curtains aim for the floor, and puddle curtains add extra length so fabric rests on the floor.
- Rod extension: Enter how far the curtain rod extends past each side of the window. A larger extension can make the window look wider and helps panels clear the glass when open; zero is allowed for inside or tight installs.
- Rod height: Enter how far above the window the rod will be mounted. Higher rods usually make the window feel taller; zero is allowed when the rod sits at the top of the window trim.
- Rod-to-floor: For floor or puddle curtains, measure from the installed rod down to the floor. This gives a better length recommendation than estimating from window height and rod height; use zero when you do not have this measurement yet.
How to measure for curtains or drapes
The most reliable curtain size comes from the rod, not only from the window. Measure the window first, then add the side extension and rod height you actually plan to use.
- Measure the window width from left to right.
- Choose how far the rod should extend past each side.
- Decide where the rod will sit above the window or near the ceiling.
- For floor or puddle styles, measure from the rod down to the floor.
- Pick the panel count and fullness before buying ready-made panels.
If you do not know the final rod height yet, start with 4 to 6 inches, or 10 to 15 cm, above the window trim. For a taller room, mounting closer to the ceiling can make the window look larger.
Curtain size chart and standard drapery lengths
Ready-made panels are usually sold by width x length per panel. Standard curtain and drapery lengths cluster around a few sizes, so it helps to know the closest store size before shopping.
| Common length | Best used for | Buying note |
|---|---|---|
| 63 in / 160 cm | Sill or short-window curtains | Often works in kitchens, bathrooms, and smaller windows. |
| 84 in / 213 cm | Common floor-length panels | A common starting point for 8 foot ceilings. |
| 95-96 in / 241-244 cm | Taller floor-length curtains or drapes | Useful when the rod is mounted higher above the trim. |
| 108 in / 274 cm | High-mounted rods and 9 foot ceilings | Often chosen for a taller, more dramatic look. |
| 120 in / 305 cm | Extra-long drapes | Best for very high rods, tall rooms, or light puddling. |
Standard curtain sizes to look for
Common ready-made panel widths include 40, 42, 50, 52, 54, 84, 100 inches, roughly 102, 107, 127, 132, 137, 213, 254 centimeters. Common lengths include 63, 84, 95, 96, 108, 120 inches, roughly 160, 213, 241, 244, 274, 305 centimeters.
When comparing packages, check whether the listed width is for one panel or for the pair. Most ready-made curtain and drape listings show the size of a single panel.
How wide should curtains or drapes be?
Total fabric width is usually wider than the rod because gathered fabric needs extra material. A standard look uses about 2x fullness, which means the combined panel widths are about twice the rod width.
1x
Flat
Minimal coverage or a simple side panel.
1.5x
Light gather
Casual curtains with less fabric bulk.
2x
Standard gather
Most ready-made curtain and drape panels.
2.5x
Full or sheer
Sheers, dressier drapes, or a softer fold.
How high to hang curtains and place the rod
For many windows, start with the rod 4 to 6 inches above the trim and 4 to 6 inches past each side. Use more height for a taller look, and more side extension when you want the panels to clear the glass when open.
Rod height
Use 4 to 6 inches above the window as a practical default. For floor-length panels, measure rod-to-floor after choosing the height.
Rod width
Add the side extension twice: window width plus left extension plus right extension. A 72 inch window with 6 inches each side uses an 84 inch rod.
How the calculation works
The calculator adds rod extension to both sides of your window, multiplies that rod width by your fullness choice, and divides the result by the number of panels. It then rounds up to common ready-made panel widths and lengths.
Curtain rod width calculator
Rod width starts with the window width, then adds the rod extension on both sides. For example, a 72 inch window with 6 inches of extension on each side uses an 84 inch rod width.
Curtain fullness calculator
Fullness compares total fabric width with rod width. Use 1x for a flatter look, 1.5x for light gathers, 2x for a standard drape, and 2.5x when you want a fuller or sheer curtain look.
Curtain length calculator
Curtain length depends on the hanging style. Sill and below-sill curtains use the window height plus rod height, while floor and puddle curtains are most accurate when you enter the measured rod-to-floor length.
How many curtain panels do I need?
Two panels are common for most windows. One panel can work for a narrow side draw, while four panels can help cover a wide rod when ready-made panels are not wide enough.
Can I use this as a drape size calculator?
Yes. Curtains, drapes, and drapery panels use the same core sizing logic: rod width, desired fullness, finished length, and panel count. Drapes often use heavier fabric, so standard or fuller gathers usually look better than a flat 1x fit.
Examples
- Wide window: Two panels, standard fullness, floor-length look using inch measurements.
- Small window: Two lighter panels for a smaller window with a below-sill finish.
- Metric window: Centimeter-based example with standard fullness and floor length.
FAQ
How wide should curtains be for a 72 inch window?
For a 72 inch window, a rod around 84 inches wide with standard 2x fullness needs about 168 inches of total curtain fabric. In metric, that is roughly a 183 cm window, 213 cm rod, and 427 cm total fabric width. That often means two extra-wide panels, or four narrower panels.
How do I measure for curtains or drapes?
Measure the window width, window height, planned rod extension on each side, and planned rod height above the window. For floor-length curtains or drapes, also measure from the installed rod down to the floor.
What size curtains do I need?
Start with rod width, not just window width. Add the rod extension on both sides, multiply by the fullness you want, then divide by the number of panels. For length, choose sill, below-sill, floor, or puddle based on where the fabric should stop.
Should curtain panels be 1.5x or 2x the window width?
Use 1.5x for a lighter, simpler look and 2x for standard fullness. Sheer curtains and decorative panels often look better closer to 2.5x.
What are standard curtain lengths?
Common ready-made curtain and drapery lengths include 63, 84, 95, 96, 108, and 120 inches. In centimeters, those are roughly 160, 213, 241, 244, 274, and 305 cm.
How wide should curtains or drapes be?
For a gathered look, total fabric width is usually 1.5x to 2.5x the rod width. A standard starting point is 2x fullness, which means the combined panel widths should be about twice the rod width.
How far should a curtain rod extend past the window?
A common starting point is 4 to 6 inches, or about 10 to 15 centimeters, past each side of the window. Wider extensions make the window look larger and let more glass show when curtains are open.
How high should I hang curtains?
A common starting point is 4 to 6 inches, or about 10 to 15 centimeters, above the window trim. Hanging closer to the ceiling can make the window feel taller, especially when using floor-length panels.
How many curtain panels do I need?
Most windows use two panels. Very wide windows, patio doors, or extra-full looks may need four panels or custom widths.
Can I use this as a drape size calculator?
Yes. Drapes usually follow the same measuring logic as curtains: rod width, fullness, panel count, and finished length. Use the fullness and hanging style controls to match the look you want.
Are curtain sizes listed per panel or total width?
Ready-made curtain sizes are usually listed per panel. If a package includes two panels, check whether the listed width is per panel or for the pair.