Measure the rod or track width (not the glass), then measure from the top of the rod or hanging rings down to the hem. Curtains hang from the rod and need fabric to fold, so rod span and fullness decide the size — get those right and 120-inch panels either work or get ruled out in five minutes.
Measure The Rod Span And The Drop, Not The Window
Measure the rod or track end to end, excluding decorative finials and end caps. Home Depot: for an outside-mount rod, measure floor to top of rod. Then the drop: The Shade Store measures curtain length from rod top to the desired end, split into sill, floor, and puddle lengths — three different measurements.
Rings and hooks change where fabric starts. If hanging from rings, measure floor to rod and floor to the bottom of the rings; ring depth is the difference between kissing the floor and floating three inches above it. Mounting type matters too — Home Depot notes inside-mount rods sit parallel to the sash with curtains ending at the sill, a shorter-curtain conversation than floor-to-ceiling drapes.
Work Out The Fullness Before You Fall In Love With A Panel
Total curtain width should be 1.5x–2x rod width for a tailored look, or 2x–2.5x for a fuller gather. Multiply rod width by the fullness factor for total finished width; divide by panel count for per-panel width. A 100-inch rod at 2x needs 200 inches total — 100 inches per panel for a pair.
Screwfix adds a step most guides skip: for a pair, add 2.5–5 cm per panel so they overlap slightly at the center, or you get a light leak down the seam.
Sizing charts often assume ~50 inches finished width per panel, but that varies by brand — check the actual listing. Width is usually listed per panel, which is why the math matters more than the package number.
A 120-inch panel sits in the standard ready-made range alongside 63, 84, 96, and 108 inches, and exists for floor-to-ceiling treatments and very tall rooms. The Shade Store frames 120 inches as the length for exactly those spaces. At a standard eight-foot ceiling, a 120-inch drape puddles far more than intended. Measure the drop first, then decide whether 120 is even on the table.
| Measurement | What To Do | Common Slip |
|---|---|---|
| Rod width | Measure end to end, excluding finials | Measuring only the glass or the frame |
| Fullness factor | Multiply rod width by 1.5x–2.5x | Skipping fullness, so panels hang flat |
| Panel width | Divide total width by panel count | Assuming 50 inches per panel works for every brand |
| Pair overlap | Add 2.5–5 cm per panel | Leaving a gap at the center seam |
| Drop length | Measure from rod top to desired hem | Measuring from the window top instead |
| Ring adjustment | Also measure to the bottom of the rings | Ignoring the ring depth entirely |
| Mounting type | Inside mount and outside mount use different math | Using outside-mount logic on an inside-mount rod |
Off-the-shelf panels come in fixed lengths, so a precise floor-to-ceiling drop usually means hemming or planning a puddle — that’s normal. Home Depot’s guide on how to measure curtains walks through both mounting styles. If you need a 120-inch panel, our roundup of tested 120 inch curtains for tall rooms covers options in that length.
Sill, Floor, Or Puddle: Pick The Finish First
Decide where the hem lands before measuring the drop; the three finishes give three numbers. Sill length stops at the windowsill and pairs with inside-mount rods. Floor length ends at the floor, as a float (a sliver of clearance) or a break (fabric touching and folding once). Puddle length pools deliberately, eating extra inches by design.
Order the measurement to match the finish: rod top to sill, rod top to floor, or rod top to floor plus intended puddle. If rings carry the panels, the drop starts at the bottom of the rings, not the rod.
FAQs
Do 120 inch curtains fit an 8-foot ceiling?
Usually not without significant puddling. An 8-foot ceiling is 96 inches, and a 120-inch panel is 24 inches longer than the wall is tall. These panels are built for floor-to-ceiling treatments and rooms taller than standard. Measure your rod height first, because 96 or 108 inches is often the right answer for typical ceilings.
Should I include curtain rings when measuring length?
Yes, if the panels hang from rings. The fabric starts at the bottom of the ring, not at the rod, so ring depth adds to usable drop. Home Depot’s guide recommends measuring both from the floor to the rod and from the floor to the bottom of the rings.
How much wider than the window should curtains be?
Total curtain width should generally run 1.5x to 2x the rod width for a standard full look, and 2x to 2.5x for a richer gather. Measure the rod end to end, excluding finials, then multiply. Panels that hit only 1x rod width hang flat and skimpy.
References & Sources
- Home Depot. “How to Measure Curtains” Covers rod-height measuring, ring adjustments, and inside versus outside mounting.
- Screwfix. “How to Measure Curtains: A Simple Guide” Source for fullness multipliers and the per-panel overlap allowance.
- The Shade Store. “How to Measure for Curtains in 5 Steps” Defines sill, floor, and puddle finishes and the 120-inch height use case.