Curtain & Drape Size Calculator

Width — the most-missed rule

Curtains hung at exact window width look stretched and undersized. The standard is 2× window width minimum for proper draping. Skimping here is the #1 reason DIY curtain projects look "off."

• 1.5× width: Casual / minimal look. OK for sheer panels and modern designs where some flat is desired.
• 2× width: Standard fullness. The default for most rooms.
• 2.5× width: Full pleated. Traditional and formal rooms.
• 3× width: Extra full / luxe. Premium hotels, formal dining, dramatic master bedrooms.

Length options by style

• Sill length: Casual rooms (kitchens, bathrooms), kids' rooms. Slightly above the sill is fine.
• Apron length: 4-6" below the window sill. Common in kitchens and over radiators.
• Floor length (just touching): Standard for living rooms and bedrooms. Most common in 2026.
• Trouser break (1/4" off floor): Tailored modern look. Helps when floors are uneven.
• Puddle (4-8" pooled): Formal, luxe. Looks gorgeous but collects dust and is impractical for high-traffic rooms.

Rod placement matters

Mount the rod 4-6" above the window trim and 4-6" wider on each side. This makes the window look taller and wider — adds the illusion of grand ceilings. The rod itself should be 8-12" longer than the window on each side, so opened curtains stack on wall rather than blocking glass.

Common widths to buy

Manufactured curtain panels come in standard widths:

• 27-30" panels: 1.5× a 36" window — 2 panels = OK casual look.
• 50-54" panels: Most common. 2 panels = ~100-108" total width = 2× a 48-50" window.
• 96-108" panels: Single wide panel — works for sliding glass doors.

Number of panels

Divide your total required width (window width × fullness) by panel width. Round UP to the nearest panel — better too much than too little.

For tested curtains and rods, see our home reviews.