How to Calculate Fabric for Wave Curtains

What Makes Wave Curtains Different

Wave curtains (also called S-fold curtains) hang in continuous, uniform S-shaped curves — not gathered pleats. The wave shape is set by the spacing of wave gliders on the track, not by how you make the heading.

This creates two important rules that differ from all other heading styles:

1. Fullness is fixed at 2.0× — you cannot adjust it
2. The track system must be compatible — standard curtain rods and basic track systems won’t work

Why the Fullness Is Exactly 2×

Wave curtains achieve their shape through glider carriers evenly spaced along the track. Each carrier holds a hook from the curtain’s heading tape. The fabric flows between carriers in curves.

The wave depth and smoothness depend on the ratio of fabric width to glider spacing:

• Too little fullness: the “waves” flatten into a near-straight panel
• Too much fullness: the waves bunch up and lose their smooth S-curve shape
• 2× fullness: the industry-standard ratio that produces clean, defined waves

You cannot use the same fabric panel with a different fullness — the wave pattern is determined by the glider count, which is set when the track is installed.

Step 1: Measure the Track Width

Wave curtains require a wave-compatible track (such as Silent Gliss 6100, Swish Sologlide, or equivalent). Measure the full track width including any return to the wall.

The “return” is the portion of track that bends back toward the wall at each end. This is typically 3”–4” on each side. The return fabric wraps around and butts against the wall for a neat, draught-free fit.

Track width input for the calculator: Use the full track width including both returns.

Step 2: Cut Width Per Panel

Finished panel width = track width ÷ number of panels
Cut width per panel  = finished panel width × 2.0 + side hems

Note: Unlike other headings, you cannot substitute a different fullness ratio. The wave pattern is set by the glider spacing, not the fabric.

Example: 100” track, 2 panels, 1” side hems per side:

Finished panel width = 100 ÷ 2 = 50"
Cut width per panel  = 50 × 2.0 + 2 = 102"

Step 3: Cut Length

Cut length = drop + heading tape allowance + bottom hem

Wave heading tape typically adds:

• Top heading allowance: 1”–1.5” (the tape folds over the top edge)
• Bottom hem: 6” (standard double-fold weighted hem)

Cut length = drop + 1.5 + 6 = drop + 7.5"

Compare to pencil pleat (4” top + 6” bottom = 10” added). Wave curtains typically add slightly less because the top heading is minimal.

Step 4: Fabric Widths Per Panel and Total

Widths per panel = ⌈ cut width ÷ fabric bolt width ⌉
Total widths     = widths per panel × panels × windows
Total yards      = (total widths × cut length) ÷ 36

Full example:

• 100” track, 2 panels, wave heading (2.0×)
• Drop: 96”, 54” fabric

Finished panel width = 50"
Cut width per panel  = 50 × 2 + 2 = 102"
Widths per panel     = ⌈ 102 ÷ 54 ⌉ = 2
Cut length           = 96 + 7.5 = 103.5"
Total widths         = 2 × 2 = 4
Total yards          = (4 × 103.5) ÷ 36 = 11.5 yards

Glider Spacing and Wave Depth

The number of gliders per metre (or per foot) of track determines the wave depth.

Standard wave glider spacings:

Most tracks come with a recommended glider spacing for their specific system. Do not mix spacings — consistent glider spacing is essential for uniform waves. For how wave heading compares to all other heading types, see Curtain Heading Types Guide.

Total gliders needed:

Gliders per panel = (track width per panel in mm) ÷ spacing + 1

Example: 500mm per panel, 80mm spacing:

500 ÷ 80 + 1 = 7.25 → 8 gliders (round up)

Heading Tape for Wave Curtains

Standard wave heading tape has evenly spaced pockets at the glider spacing interval. You sew the tape to the back of the top hem, then insert wave hook carriers into the pockets.

Tape options:

• Fixed-pocket tape: pockets are evenly spaced, carrier positions are fixed
• Adjustable-pocket tape: pocket spacing can be set during installation

Always buy tape from the same manufacturer as your track — hook types are not always interchangeable between brands.

Tape to buy:

Tape length per panel = cut width per panel (one continuous length)
Total tape = sum of all panel cut widths
Add 4" per panel for turning in at edges

Wave Curtains vs. Pencil Pleat: Fabric Comparison

On 100” track, 2 panels, 96” drop, 54” fabric:

Wave curtains use notably less fabric than pencil pleat on wide windows (because the fullness ceiling at 2× means fewer widths needed). But the track hardware cost is significantly higher than a standard pole-and-rings setup. For the most formal, fabric-intensive option, see How to Calculate Fabric for Pinch Pleat Curtains.

Use the Curtain Fabric Calculator — select “Wave / S-Fold” to calculate wave curtain fabric automatically.

See also: Curtain Heading Types Guide and Lined vs Unlined Curtains: How Lining Affects Fabric Needs.