Step 1: Measure the Width (Determine Rod/Track Length and Placement)
If the rod or track is installed, measure its usable end-to-end span without decorative finials and record the result.
If the hardware is not installed, decide the mounting position before ordering:
Measure with a retractable metal tape: keep it level and taut, write every result immediately, and repeat each measurement before entering a custom size.
Height above the window frame: a common starting point is 6–10 inches above the frame. Check the wall, ceiling, brackets, and finished curtain length before marking the position.
Width beyond the window frame: a common starting point is 6–15 inches on each side so the panels can stack away from the glass.
Usable hardware width: measure the travel span, not the glass width and not the decorative finials.
Rod or track widthRecord the usable end-to-end travel span, excluding decorative finials.
Mounting heightChoose the position first, then confirm brackets, ceiling clearance, and the finished length.
Side extensionPlan enough extension for stack space and the desired glass reveal.
Hardware to floorMeasure from the correct rod, ring, hook, or track reference for the selected header.
Record the hardware width and placement separately from the window-frame width.
Step 2: Know the Fullness of Each Header Style
Fullness is how much fabric goes into the folds compared with the width the curtain covers. Pleated and ripple fold headers are sewn with it, so you order the finished width. Soft top and grommet panels are made flat, so you multiply the rod length by the fullness you want.
Order by the panel: enter the width of one panel and choose the number of panels separately.
Pleated Styles: 2x to 2.3x Built In
Pinch pleat, pinch pleat with back tab, tailor pleat, inverted box pleat and goblet headers are sewn with about 2x fabric (200%). Triple pleat and triple tailor pleat headers use about 2.3x (230%). The width you order is the finished width across the pleats, so it can match the rod.
Single panel width = rod length ÷ number of panels: a 100-inch rod takes one 100-inch panel or two 50-inch panels.
For an even fuller look you can order about 1.25x the rod length, roughly two 62-inch panels on a 100-inch rod. This is optional.
Measure the length from the eye ring of the pin hook to the floor or your chosen endpoint.
When open, each panel stacks to about 20% of its width: roughly 10 inches for a 50-inch panel.
Pleats are sewn with about 2x or 2.3x fabric, so the ordered width is the finished width.
Soft Top and Grommet Styles: Add 1.5x to 2x
Tab top, back tab, rod pocket, Flat Hooks and 4-in-1 headers (the soft top group) and grommet panels are made at 1x: the width you order is the flat width of one panel, fully spread out. Multiply the rod length by 1.5x for a lighter, tailored gather or by 2x for a full gather (recommended), then divide by the number of panels.
1.5x on a 100-inch rod: 100 × 1.5 ÷ 2 = two 75-inch panels.
2x on a 100-inch rod: 100 × 2 ÷ 2 = two 100-inch panels.
Ordering only the rod length (1x) leaves the panels almost flat when closed.
When open, the panels stack to about 20% of the width they cover: roughly 10 inches per side on a 100-inch rod.
Length: measure from the top of the rod for grommet, tab top, back tab and rod pocket hanging. Flat Hooks and the 4-in-1 hook belt hang from rings, so measure from the ring eyelet.
From flat (left) to closely gathered (right): a soft top or grommet panel ordered at the rod length looks flat; 1.5x and 2x add progressively fuller folds.
Step 3: Work Out the Order Width and Length
Every example below uses the same window: 80 inches wide, with a rod or track 100 inches long from end to end (10 inches past each side of the frame) and two panels unless noted.
Compare how the finished width, stack, attachment point, and length reference change across the four header categories.
Pleated
Order width = finished width: 100 ÷ 2 = two 50-inch panels.
Built-in fullness is about 2x (2.3x for triple pleats); do not multiply again.
Optional fuller look: about 1.25x the rod, roughly two 62-inch panels.
Open stack: about 20% of each panel, roughly 10 inches per side.
Length: from the eye ring of the pin hook to the floor or your chosen endpoint.
Soft Top (Tab Top, Back Tab, Rod Pocket, Flat Hooks, 4-in-1)
Order width = flat width: (rod length × fullness) ÷ number of panels.
1.5x for a lighter gather: 100 × 1.5 ÷ 2 = two 75-inch panels.
Open stack: about 20% of the covered width, roughly 10 inches per side.
Length: from the top of the rod to the floor or your chosen endpoint.
Ripple Fold
Order width = finished width: one 100-inch panel, or two 50-inch panels.
Built-in fullness is about 2x fabric in the waves; do not add extra width.
Hang it on a track with carriers that match the ripple fold tape.
Installed track: measure from the bottom of the track to the floor or your chosen endpoint.
Track not yet installed: mounting height − track height − floor clearance, for example 96 − 1 − 1 = 94 inches.
Order-width formulas
Each formula gives the width of one panel. Enter that width and choose the number of panels separately.
Pleated: single panel width = rod length ÷ number of panels.
Soft Top: single panel width = (rod length × 2) ÷ number of panels; use × 1.5 for a lighter gather.
Grommet: single panel width = (rod length × 2) ÷ number of panels; use × 1.5 for a lighter gather.
Ripple Fold: single panel width = track length ÷ number of panels.
Finished width or flat width?
Finished width (pleated, ripple fold): the fullness is sewn in, so a 100-inch rod with two panels takes two 50-inch panels. Enter 50 inches and a quantity of 2.
Flat width (soft top, grommet): multiply first. At the recommended 2x, 100 × 2 ÷ 2 = 100, so enter 100 inches and a quantity of 2.
Do not add fullness twice: two 100-inch pleated panels on a 100-inch rod would carry about four times the fabric and crowd the rod.
Example: 80-inch window, 100-inch rod or track
Header style
Fullness
Panels
Width to order (each panel)
Length measured from
Pleated
2x–2.3x, built in
2
50 inches
Eye ring of the pin hook
Soft Top
1.5x, added
2
75 inches
Rod top (tab top, back tab, rod pocket) or ring eyelet (Flat Hooks, 4-in-1 hook belt)
Soft Top
2x, added (recommended)
2
100 inches
Same as above
Grommet
2x, added (recommended)
2
100 inches
Rod top
Ripple Fold
About 2x, built in
1 or 2
100 inches, or 50 inches each
Track bottom
Step 4: Choose the Finished Length and Placement
Decide the endpoint before entering a custom length. Measure every opening independently, even when windows appear identical.
Use the same hardware width and top reference while comparing sill, below-sill, floor, slight-break, and puddle lengths.
Sill Length
Ends around the sill area. Confirm the desired reveal and keep the panel clear of handles or furniture.
Apron Length
Falls below the sill. Confirm the visual endpoint and any wall trim or radiator clearance.
Floor Length
Finishes at or just above the floor for a clean, frequently used installation.
Break Length
Uses a small amount of extra fabric to create a soft break at the floor.
Puddle Length
Adds fabric on the floor for a decorative look. Best suited to low-traffic placements.
Ripple-fold length
Installed track: use the attachment reference specified for the compatible track. If that system measures from the bottom of the track, measure from that point to the finished endpoint.
Uninstalled track: confirm the exact track and connector first. For a bottom-of-track reference, planned track-top height − track height − curtain-to-floor clearance = curtain length.
Final measuring check
Use the same unit throughout.
Measure at least twice.
Record each window separately.
Match the measurement reference to the selected header.
