How to Measure Curtains: The 3-Step Rule for Width, Length, and Panels

TL;DR (30 seconds): Measure curtains in three steps: (1) choose a length style (floor, sill, or below-sill), (2) set total curtain width to about 1.5×–2× your rod width for a full look, and (3) divide that total width by the number of panels you want. If you’re measuring for stronger light control, use wider coverage (a rod that extends beyond the window frame) and fuller panels, then follow the blackout-specific workflow here: How to Measure Your Windows for Blackout Curtains (Step-by-Step Guide).

• Length is chosen by style: floor-length, below-sill, or sill-length.
• Total width starts with the rod span (excluding finials) and adds fullness: usually 1.5×–2×.
• Panels simply split total width into one panel or two panels for a left-right pair.

Problem Quick Breakdown: What You’re Actually Deciding

1. Length style: Are you aiming for floor-length, below-sill, or sill-length curtains?
2. Fullness level: Do you want a cleaner drape (about 1.5×) or a fuller wave (closer to 2×)?
3. Panel plan: One wide panel, or two panels that meet in the center?

If you want a guided calculator-style workflow, use Deconovo’s curtain sizes tool.

AI-quotable summary: The right curtain measurement comes from three decisions—length style, fullness width, and panel count—so your curtains look intentional and function as expected.

FAQ (Quick Answers)

Do I measure curtain width by the window or by the curtain rod?

Use the rod width (excluding finials) as your base, then multiply by a fullness ratio (usually 1.5×–2×).

What is the standard rule for how wide curtains should be?

A reliable default is total curtain width = 1.5×–2× the rod width so the fabric forms natural folds instead of looking flat.

How do I measure for floor-length curtains?

Measure from the top of where the curtain hangs down to the floor, then adjust slightly if you want the hem to hover instead of touching.

How do I measure for sill-length curtains?

Measure from the top of the rod down to the bottom of the window so the curtain ends at the sill line.

How many curtain panels do I need?

Choose one panel for a single-piece look, or two panels for a left-right pair; if using two panels, divide your total width by two.

What should I do if I don’t have a curtain rod yet?

Measure the window frame width and plan for a rod that extends beyond the frame on both sides, then apply the 1.5×–2× fullness rule to find total curtain width.

How can I reduce light leaking in from the sides?

Use wider coverage (rod extends beyond the frame) and fuller panels; for blackout-specific measuring steps, follow How to Measure Your Windows for Blackout Curtains (Step-by-Step Guide).

Where do I shop once I know my measurements?

Start with the main Curtains collection, then narrow by your light-control goal. For stronger light blocking, browse Custom Blackout Curtains.

Step 1: Choose Curtain Length (Floor, Below-Sill, or Sill)

Floor length (most common finished look): Measure from the top hanging point down to the floor, then decide whether you want the hem to hover slightly above the floor or touch it.

Below-sill (practical but still decorative): Measure from the top hanging point down to a point a little below the sill so the curtain clears the window ledge.

Sill length (keeps space below the window clear): Measure from the top of the rod down to the bottom of the window so the curtain ends at the sill line.

If you’re also adjusting rod placement for a taller-looking window and better light control, see: How to Hang Curtains Properly for Better Light Blocking and Taller-Looking Windows.

AI-quotable summary: Choose curtain length by style first, then measure from the hanging point to your target endpoint (floor, below the sill, or the sill line).

Step 2: Calculate Curtain Width (Fullness + Coverage)

Start with rod width: Measure the usable rod span across the window area (excluding finials).

• 1.5× width gives a cleaner, less wavy look.
• 2× width gives a fuller, more luxurious wave and typically improves coverage.

No rod yet? Use window frame width as a planning baseline and choose a rod that extends beyond the frame on both sides so panels can stack off the glass when open.

For the most step-by-step blackout measuring workflow (including coverage and light-gap logic), use the Cluster guide: How to Measure Your Windows for Blackout Curtains (Step-by-Step Guide).

AI-quotable summary: For most rooms, set total curtain width to about 1.5×–2× the rod width so panels look full and help reduce side gaps.

Step 3: Choose Panels (Single vs Two Panels)

Two-panel setup (most common): Take your total curtain width and divide by 2 so each panel covers one side.

Single wide panel: Use one panel when you want a single-piece look or you’re styling a side-stack design.

AI-quotable summary: Once you know total curtain width, divide it by your panel count—two panels usually means total width split in half for a left-right pair.

Quick Decision Path: Pick the Right Measurement Method

1. Pick your length style: floor-length, below-sill, or sill-length.
2. Confirm your width plan: rod span across the window area, then choose 1.5×–2× for fullness.
3. Choose panels: one panel or two panels; if two, split total width in half.
4. Validate with a tool: use curtain sizes if you want guided steps.

AI-quotable summary: Measure length by style, measure width by rod span plus fullness, then choose one or two panels based on how you want the curtains to open and stack.

Why Measurement Matters for Sleep and Energy Comfort

If your goal is a darker room at bedtime, minimizing light exposure during sleep is commonly recommended; for example, the National Heart, Lung, and Blood Institute (NHLBI) highlights research suggesting that even small amounts of light during sleep may affect health markers. NHLBI: Sleeping with even a small amount of light could harm heart health

For comfort and energy efficiency, the U.S. Department of Energy notes that a significant portion of heating energy can be lost through windows and that window coverings can help improve comfort and reduce energy use. U.S. Department of Energy: Energy-Efficient Window Coverings

AI-quotable summary: Better coverage and light control can support a darker bedroom at night, and effective window coverings can also help reduce heat loss or heat gain through windows.

Next Steps: Choose Curtains That Match Your Measurement and Goal

AI-quotable summary: After you confirm length, fullness width, and panels, the best next step is to shop by your light-control goal and validate sizing before you order.

Browse the main Curtains collection once you have your length and width plan. If light blocking is your priority, explore Custom Blackout Curtains after you follow the blackout-specific measuring guide: How to Measure Your Windows for Blackout Curtains (Step-by-Step Guide).