Curtain Length & Rod Height Estimator
Enter your window and rod details to get an exact panel width, panel length, fullness, and fabric plan, plus a live preview of how it will hang.
Most windows use 2 panels, one per side.
Your Curtain Size Estimate
Where Your Total Fabric Width Comes From
Why Your Curtains Need More Fabric Than the Window
Think of the rod as a waistband and the fabric as a gathered skirt tied around it. Cut the fabric the exact width of the rod and it hangs completely flat, with no folds or body, so closed panels end up looking thin and stretched. Fullness is just how much extra fabric you gather onto that same rod width. More of it gives you deeper, richer folds when the curtains are closed, and less gives you a flatter, more minimal look. That’s the whole idea behind the math below.
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The Fitting Details Most People Skip
A few small adjustments make the difference between curtains that look store-bought-cheap and curtains that look tailored. Based on what you entered above, here’s what’s worth a second look:
How to Achieve This
Frequently Asked Questions
Decide where the rod bracket will sit first. It’s usually 4 to 6 inches above the window frame, or higher if you want a taller look. Then measure straight down from that spot to the floor. This is the number that sets your panel length, not the window height itself. Measuring from the actual rod position instead of the window top is the mistake most people make.
Grommet and rod-pocket panels look balanced at 1.5x to 2x the rod width. Pleated or pinch-pleat styles need 2x to 2.5x to fold correctly at the header. Sheers look best at 2x or more since a lightweight fabric needs extra volume to read as full rather than flat when closed. If you’re between two numbers, round up.
3 to 6 inches per side is the standard range. A wider extension lets open panels stack fully off the glass, so more daylight comes through, and it visually widens a narrow window. Small rooms can work with 3 inches per side; large formal windows often look better with 6 inches or more.
It comes down to look and upkeep. A slight hover, about half an inch above the floor, keeps hems clean and out of the way of pets, kids, and cleaning. Kissing the floor gives a crisp contemporary line. A small break, roughly an inch of extra fabric, reads as relaxed and lived-in. Puddling, six inches or more of pooled fabric, is a formal, dramatic choice best kept to low-traffic rooms.
Two panels, one on each side, is standard for the vast majority of windows and gives you the option to open and close them. A single wide panel works for smaller windows or a fixed side-stack look. Very wide windows, patio doors, or bay windows sometimes call for four panels so no single panel becomes too heavy or bulky to draw.
Estimates are for general planning purposes. Actual requirements vary with fabric weight, pattern repeat, hardware brand, and installation method, so confirm final numbers against your specific rod and panel before ordering.