Curtain Fabric Yardage Formula: How the Calculation Works

The Four-Step Curtain Fabric Formula

Curtain fabric calculation always follows the same four steps, regardless of heading style.

Step 1: Cut Width Per Panel

Cut width = (pole width ÷ number of panels) × fullness ratio + (side hems × 2)

• Pole width = full width of pole or track (including overhang)
• Number of panels = typically 2 (one per side)
• Fullness ratio = depends on heading style (see table below)
• Side hems = typically 1.5” per side = 3” total

Example: 72” pole, 2 panels, pencil pleat (2.25× fullness), 1.5” side hems:

Panel finished width = 72 ÷ 2 = 36"
Cut width = 36 × 2.25 + 3 = 84"

Step 2: Widths Per Panel

Widths per panel = ⌈ cut width ÷ fabric bolt width ⌉   (round UP)

Always round up — you cannot use a fraction of a fabric width.

Example: 84” cut width on 54” fabric:

Widths per panel = ⌈ 84 ÷ 54 ⌉ = ⌈ 1.56 ⌉ = 2 widths per panel

At 2 widths per panel with 2 panels: 4 fabric widths total.

Step 3: Cut Length

Cut length = drop + top hem + bottom hem

Standard hem allowances:

• Top hem: 4” (double-fold: 2” × 2)
• Bottom hem: 6” (double-fold: 3” × 2)
• Rod pocket: add 4” to cut length for the pocket header

With pattern repeat:

Cut length (with repeat) = ⌈ raw cut length ÷ repeat ⌉ × repeat

Example: 90” drop + 4” top + 6” bottom = 100” raw cut length. Pattern repeat = 8”:

⌈ 100 ÷ 8 ⌉ = 13  →  13 × 8 = 104" cut length
Waste per width: 4"

Step 4: Total Fabric

Total fabric (inches) = widths per panel × panels × windows × cut length
Total yards           = total inches ÷ 36
Total metres          = total inches × 0.0254

Full example:

• 72” pole, 2 panels, pencil pleat (2.25×)
• Drop: 90”, hems: 4” top + 6” bottom = 100” cut length
• No pattern repeat
• 54” fabric

Cut width = (72 ÷ 2) × 2.25 + 3 = 84"
Widths/panel = ⌈ 84 ÷ 54 ⌉ = 2
Total widths = 2 × 2 = 4
Total inches = 4 × 100 = 400"
Total yards  = 400 ÷ 36 = 11.1 yards

Fullness Ratios by Heading Style

Bold rows indicate the highest-fabric headings. Pinch pleat (3-finger) uses the most fabric of any standard heading. For step-by-step pinch pleat fabric calculation, see How to Calculate Fabric for Pinch Pleat Curtains.

Standard Hem Allowances (Reference)

Double-fold hems are standard for unlined curtains. Lined curtains typically have a single-fold top hem and a weighted hem at the bottom. For lining fabric quantities and lining type comparison, see Lined vs Unlined Curtains.

Pattern Repeat: Waste Table

For a 6-width curtain job (typical for one pair of panels on a wide window):

Large repeats (12”–18”) can add a full extra yard on a typical curtain job.

Quick Reference: Fabric Bolt Widths

Use the Curtain Fabric Calculator to run the full calculation for your specific measurements.

See also: Curtain Heading Types Guide and How to Measure Windows for Curtains.