What this calculator decides, and what it leaves to you
"How long should my curtains be?" is really two questions wearing one coat: where does the rod go, and where does the hem land. Most of the length advice online answers the second and skips the first, which is backwards, because the rod position is the number that changes how the whole room reads. This tool decides the rod first, from your ceiling and your window, then runs the hem rule for the look you picked and draws the result on a scale elevation of your wall so you can see the proportion before you buy a yard of fabric. What it leaves to you is taste: the room pills suggest what most people choose, and the look pills override that whenever you disagree. For panel width, fullness, rod length, and yardage, hand the same window to the window measurement tool; the two are built on the same rules and meant to be used together. Both are companions to our complete measuring guide, which explains why every rule exists.
Why designers hang curtains higher than most people expect
Walk into a room a good designer has finished and the curtain rod is almost never where a first-time homeowner would have put it. The instinct is to mount the rod just above the window trim, a couple of inches up, because that's where the window is. The designer mounts it 6 inches below the ceiling, or on the ceiling itself, and the room looks a foot taller for it. The trick is simple optics. Fabric hung from near the ceiling draws a continuous vertical line from the crown to the floor, and your eye reads the whole line as the window's height. Hang the rod at the frame and the eye reads the frame instead, which in most houses is a 5 foot window sitting in an 8 foot wall with a lot of dead drywall above it.
The second half of the trick is what happens at the bottom. Higher rod, longer panel, and the panel needs to reach the floor to complete the line; a curtain hung high that stops at the sill just looks like a curtain hung high. Which is why the standard advice, 4 to 6 inches above the frame, is the floor of the range rather than the target. In a standard 8 foot room we usually mount within 6 inches of the ceiling. In 9 and 10 foot rooms we'll go two thirds of the way from the frame to the ceiling, or all the way up, depending on how much wall there is to fill. The only things that stop us are the brackets, which need about 2 inches of clearance below the ceiling or the crown, and the budget for fabric, since every inch of rod height is an inch of panel on both sides. A Craftsman in Pasadena with 9 foot ceilings and a 12 inch deep head casing is a good example: the rod goes 3 inches above that casing so the trim stays visible, the panels run 105 inches to a float, and the window reads as tall as the room.
When to break the rules
Transom windows are the first exception. If there's a fixed pane above the operable window, treat the transom's top as the frame top and hang above it; covering a transom with fabric at rod height is the one way to make a tall window look short. Low ceilings are the second. In a 7 foot 6 basement or a converted attic, the ceiling-high rod puts the heading in the sightline of anyone standing, so we mount a hand's width above the frame and let the length do the work. Drop ceilings, soffits, and crown molding deeper than 5 inches all push the rod down for the same bracket-clearance reason; enter the crown depth above and the calculator accounts for it. Radiators, window seats, and kitchen counters end the floor-length conversation entirely and turn it into a sill or apron one. And in double-height rooms, going all the way up can strand the window in a sea of fabric; there we'll hang 12 to 18 inches above a 10 foot frame and let the proportions breathe, which is the kind of judgment call a free in-home measurement exists for in LA and Ventura counties.
Frequently asked questions
How high should curtain rods be above the window?
The textbook answer is 4 to 6 inches above the frame, and the better answer in most rooms is higher. Mounting the rod two thirds of the way from the frame to the ceiling, or within about 6 inches of the ceiling in a standard 8 or 9 foot room, makes the window read taller and the ceiling higher for the price of a little extra fabric. The only hard limit is bracket room: leave about 2 inches below the ceiling or the bottom edge of any crown molding. The calculator applies those rules for you and tells you when it had to adjust.
Should curtains touch the floor?
Yes, in any room that isn't a kitchen, a bathroom, or a room with something under the window, and the only real question is how they meet the floor. A float stops a half inch above it and is the length we recommend to most families, because it hangs dead straight and never collects dust or dog hair. A kiss just touches, which looks the most tailored and shows every quarter inch a floor is out of level. A break adds an inch or two of soft fold, and a puddle adds 6 to 12. Curtains that stop a few inches above the floor, the classic ready-made mistake, look like pants that shrank in the wash.
What are standard curtain lengths?
Ready-made panels come in 63, 84, 96, 108, and 120 inch lengths, with 95 occasionally standing in for 96. Those numbers exist because they're convenient to manufacture, not because rooms come in those sizes. An 8 foot ceiling with the rod hung high wants roughly 91 to 95 inches, a 9 foot ceiling wants 103 to 107, and stock sizing lands on neither. That gap between the stock number and the number your room needs is the whole reason custom lengths exist, and it's what this calculator measures.
What length curtains for 9 foot ceilings?
With the rod mounted about 6 inches below a 108 inch ceiling, the rod sits at 102 inches and a floating hem lands at 101½; a kiss is 102, a small break about 103½. Stock 108 inch panels hung from that rod pool 6 unplanned inches on the floor, and 96 inch panels stop 6 inches short, so 9 foot rooms are where people most often discover that stock lengths don't fit. If you'd rather hang the rod at a standard 6 inches above the frame, the panel length follows the frame, not the ceiling; enter both numbers above and the calculator shows you each option.
What length curtains for 8 foot ceilings?
A 96 inch ceiling with the rod 6 inches below it puts the rod at 90 inches, so a floating hem is 89½, a kiss is 90, and a break is about 91½. That's why 84 inch stock panels look wrong in most 8 foot rooms when the rod is hung high: they end 5 or 6 inches above the floor. Hung at 4 to 6 inches above a typical frame instead, the rod lands closer to 88 or 89 inches and an 84 still comes up short. Eight foot rooms almost always want a custom length in the high 80s to low 90s, cut to the half inch.
How much should curtains puddle?
Six to eight inches is the sweet spot for a real puddle; 2 to 4 inches reads as a mistake rather than a choice, and past 12 the fabric starts to look like it's collapsed. The fabric matters as much as the number: soft linen, silk, and lightweight velvet fold into a puddle gracefully, while stiff or heavily interlined drapery just buckles. Puddles suit dining rooms, formal living rooms, and bedrooms that don't get daily vacuum traffic, and they need a minute of re-fluffing every time the floor gets cleaned. The calculator's formal option uses 8 inches and shows 6 and 12 as alternatives.