Curtain Size Calculator

Width Calculation

1. Effective rod width = rod/track width + (2 × side return/overlap)
2. Total fabric width = effective rod width × fullness ratio
3. Number of panels = total fabric width ÷ standard panel width (rounded up)

Length Calculation

1. Base length depends on the selected style:
   • Sill: window height + rod height above window − 0.5 in (1 cm) clearance
   • Below sill: sill length + 4 in (10 cm)
   • Floor: window height + rod height above window + bottom-to-floor distance − 0.5 in (1 cm) clearance
   • Puddle: floor length + 2.5 in (6 cm) extra
2. Finished length = base length
3. Cut length = finished length + hem & header allowance

Fullness Ratio Guide

• 1.5x — Minimal fullness, flat or casual look
• 2x — Standard fullness, works for most curtains
• 2.5x — Deluxe fullness, ideal for pinch pleats and formal drapes
• 3x — Ultra full, best for sheer fabrics and luxury drapery

Tips

• Mount the curtain rod 4–6 inches above the window frame for a taller appearance
• Extend the rod 3–6 inches beyond each side of the window to let in maximum light when curtains are open
• Floor-length curtains should hover about 0.5 inches above the floor
• Add extra hem allowance for patterned fabrics that need pattern matching
• For a pair of curtains covering one window, each panel should be half the total fabric width