🪟 Curtain Size Calculator

Calculate the perfect curtain dimensions for your windows based on window width, height, and desired fullness style. Supports both inches and centimeters.

📏 Select Unit System:

📐 Inches 📏 Centimeters

Window Width

Full width of your window frame

Window Height

Height from top of frame to sill

Fullness Style

Determines how gathered the curtains look

Length Style

Where the curtain hem should fall

Number of Panels

Typical: 1 (single panel) or 2 (pair)

Real-World Curtain Size Examples

🪟 Standard Living Room Curtains

A 48-inch wide window with 60-inch height, using standard 2x fullness with apron length. Two panels.

Fullness ratio: 2.0x

Panel width: (48 × 2.0) ÷ 2 = 48 inches per panel

Panel length: 60 + 6 = 66 inches (apron length)

Fabric per panel: 48 × 66 inches

Total fabric needed: (2 × 48 × 66) ÷ 36 = ~5.5 yards

This gives a classic, elegant gather for living room drapes.

🚿 Bathroom Sill Curtain

A 36-inch wide window with 48-inch height, using 1.5x rod pocket fullness with sill length. Single panel.

Fullness ratio: 1.5x

Panel width: 36 × 1.5 = 54 inches

Panel length: 48 + 1 = 49 inches (sill length)

Total fabric needed: (54 × 49) ÷ 36 = ~1.8 yards

Rod pocket curtains use less fullness for a cleaner, more tailored look.

🛏️ Floor-Length Bedroom Drapes

A 72-inch wide sliding door with 84-inch height, using 2.5x pleated fullness with floor length. Two panels.

Fullness ratio: 2.5x

Panel width: (72 × 2.5) ÷ 2 = 90 inches per panel

Panel length: 84 + 0.25 = 84.25 inches (floor length, slight clearance)

Fabric per panel: 90 × 84.25 inches

Total fabric needed: (2 × 90 × 84.25) ÷ 36 = ~10.5 yards

Pleated curtains create a luxurious, tailored look for formal bedroom settings.

🍳 Kitchen Cafe Curtains

A 30-inch wide kitchen window with 36-inch height, using 2x standard fullness with sill length. Single valance panel.

Fullness ratio: 2.0x

Panel width: 30 × 2.0 = 60 inches

Panel length: 36 + 1 = 37 inches (sill length)

Total fabric needed: (60 × 37) ÷ 36 = ~1.7 yards

A single cafe curtain panel uses less fabric while still providing a nice gather.

Understanding Curtain Size Calculation

Choosing the right curtain size is essential for achieving the perfect look and function for your windows. The key is understanding fullness ratio — the amount of fabric relative to the window width that creates the gathered look — and length styles that determine where the curtain hem falls.

Core Formulas

Panel Width = (Window Width × Fullness Ratio) ÷ Number of Panels

The width of each curtain panel, accounting for fullness style

Total Fabric Width = Window Width × Fullness Ratio

Total fabric required across all panels to achieve the desired gather

Panel Length = Window Height + Length Adjustment

Sill: +1 in / Sill: +2.5 cm | Apron: +6 in / Apron: +15 cm | Floor: +0.25 in / Floor: +0.6 cm

Fullness Ratios by Curtain Style

The fullness ratio determines how gathered or flat your curtains will look:

Rod Pocket (1.5x) — Minimal gathering, clean and tailored look. Best for casual settings, kitchens, and bathrooms. Uses 1.5 times the window width.
Standard (2x) — Classic fullness, versatile and popular. Works well for most living rooms, bedrooms, and dining areas. Uses 2 times the window width.
Pleated (2.5x) — Rich, elegant fullness ideal for formal spaces. Creates deep, defined pleats. Uses 2.5 times the window width.
Extra Full (3x) — Luxurious, dramatic fullness for grand windows and formal settings. Uses 3 times the window width.

Length Styles Explained

Choose where your curtain hem should fall:

Sill Length — Curtain hem ends at the window sill. Adds window height + 1 inch (2.5 cm). Ideal for kitchens, bathrooms, and windows above sinks.
Apron Length — Curtain hem extends below the sill. Adds window height + 6 inches (15 cm). The most popular choice for most rooms — covers the sill but doesn't reach the floor.
Floor Length — Curtain hem just barely touches (or hovers above) the floor. Adds window height + 0.25 inches (0.6 cm) for a slight clearance. Creates a dramatic, elegant look for formal spaces.

How to Measure and Calculate Step by Step

Measure window width: Measure the full width of your window frame. For inside-mount curtains, measure the inside width of the window frame. For outside-mount, measure the width you want the curtain rod to cover (usually 4-8 inches wider than the frame).

Measure window height: Measure from the top of the window frame (or curtain rod position) to where you want the curtain to end (sill, apron, or floor).

Choose fullness style: Decide how gathered you want the curtains — rod pocket (1.5x), standard (2x), pleated (2.5x), or extra full (3x). Multiply window width by this ratio to get the total fabric width needed.

Decide on panels: Divide the total fabric width by the number of panels (typically 2 for a pair). This gives you the width of each panel.

Calculate panel length: Add the appropriate length adjustment based on your chosen length style (sill, apron, or floor).

Convert to yardage: Calculate total fabric area (panel width × panel length × number of panels), then divide by 36 (inches to yards) or 100 (cm to meters) to get total fabric needed for purchasing.

Quick Tips for Measuring Windows

📐 Measure Twice

Always measure your window at least twice and record the largest dimension. Windows are often slightly uneven, so use the widest measurement for the safest fit.

🔄 Rod Placement Matters

Mount curtain rods 4-6 inches above the window frame to make ceilings appear higher. This also allows more natural light when curtains are open.

➕ Add Extra for Hemming

Add 4-6 inches (10-15 cm) to your final length calculation for top and bottom hems. Our calculator's built-in adjustments account for standard hem allowances.

🧺 Consider Shrinkage

Natural fiber curtains (cotton, linen) can shrink 3-5% after washing. Add an extra 5-10% to your yardage or pre-wash before hemming.

How to Choose the Right Curtain Size

Choosing the right curtain size involves more than just measuring your window. The key factors are fullness (how gathered the fabric looks), length (where the hem falls), and rod placement (above or inside the window frame). Getting these right transforms a room from ordinary to professionally decorated.

The fullness ratio determines the amount of fabric relative to the window width. A 2x fullness (standard) means you need twice the window width in fabric. This creates the classic gathered look that most people expect from curtains. A 1.5x ratio (rod pocket) gives a flatter, more tailored appearance, while 2.5x (pleated) or 3x (extra full) delivers a richer, more luxurious drape.

The length style affects both aesthetics and practicality. Sill-length curtains are ideal for windows above sinks, radiators, or shelves. Apron-length curtains are the most versatile — they cover the sill but don't touch the floor, making them suitable for most standard windows. Floor-length curtains create a dramatic, elegant look and are ideal for formal living rooms, dining rooms, and bedrooms.

Measuring Tips

Width: For inside-mount, measure the inside width of the window frame. For outside-mount, add 8-12 inches to the window width (4-6 inches per side) to allow curtains to stack back when open.
Height: For outside-mount rods, mount 4-6 inches above the window frame. This makes the ceiling appear higher and allows more light through the top of the window.
Stack back: When curtains are fully open, they should not block the window glass. Ensure your rod extends far enough beyond the frame to accommodate the stacked fabric.
Floor clearance: For floor-length curtains, maintain a 0.25-0.5 inch gap between the hem and the floor to prevent the fabric from touching the ground and collecting dust.

Curtain Width and Fullness Guide

The amount of fullness you choose dramatically affects the final look of your curtains. Here's a guide to help you decide:

🪟 Rod Pocket (1.5x)

Best for casual settings like kitchens and bathrooms. The fabric slides directly onto the rod, creating a simple gathered look with minimal fullness. Uses 1.5 times the window width.

🏠 Standard (2x)

The most popular choice for general use. Creates a classic, balanced gather that works in any room. Uses twice the window width. Perfect for living rooms, bedrooms, and dining areas.

🏛️ Pleated (2.5x)

Ideal for formal settings and larger windows. Creates deep, defined pleats for an elegant, tailored appearance. Uses 2.5 times the window width. Often paired with pinch-pleat or pencil-pleat heading tape.

👑 Extra Full (3x)

Luxurious fullness for grand, dramatic windows. Creates rich, opulent drapes that make a statement. Uses 3 times the window width. Best for formal living rooms, bay windows, and high-ceilinged spaces.

Frequently Asked Questions

How do I measure my window for curtains?

To measure for curtains, first decide if you want inside-mount (within the window frame) or outside-mount (on the wall above the frame). For outside-mount, measure the width of your window and add 8-12 inches for proper coverage and stack-back. For height, measure from where the curtain rod will be placed (typically 4-6 inches above the frame) down to your desired endpoint (sill, apron, or floor). Always take measurements at three points and use the largest value, as windows are often not perfectly square.

What is curtain fullness and why does it matter?

Curtain fullness refers to the ratio of fabric width to window width. A 2x fullness means you need twice the window width in fabric. Fullness matters because it determines the gathered look of your curtains: too little fullness makes curtains look flat and skimpy; too much can look bulky and overwhelming. Standard fullness (2x) is recommended for most applications. Rod pocket curtains use 1.5x for a tailored look, while pleated and formal curtains use 2.5x-3x for a luxurious appearance.

How much wider than the window should curtains be?

For a standard outside-mount installation, your curtain rod should extend 4-6 inches beyond each side of the window frame, making the total rod width 8-12 inches wider than the window. This allows curtains to stack back off the glass when open, maximizing natural light. The curtain panels themselves should be 2-3 times the window width in total fabric (before dividing into panels) to achieve proper fullness when closed. Our Curtain Size Calculator handles all these calculations automatically.

What length should curtains be — sill, apron, or floor?

The best curtain length depends on your room and window location: Sill length (ends at the window sill) is ideal for kitchens, bathrooms, and windows above furniture or radiators. Apron length (extends 4-6 inches below the sill) is the most popular choice — it offers a neat finish while covering the sill. Floor length (ending just above the floor) creates an elegant, formal look perfect for living rooms, dining rooms, and bedrooms. For floor-length curtains, maintain a 0.25-0.5 inch gap from the floor to prevent the fabric from touching the ground.

How many curtain panels do I need for a window?

Most windows look best with two panels — one on each side — as this creates a balanced, symmetrical look and allows you to open curtains from the center. For very narrow windows (under 30 inches), a single panel may suffice. For wide windows or sliding doors, you may need 3-4 panels. Our calculator lets you specify the number of panels, and each panel's width is calculated as the total fabric width divided by the number of panels.

Should I buy extra fabric for curtain hems?

Yes, always add extra for hems! Standard curtain construction requires 3-4 inches for the top hem (rod pocket or heading tape) and 2-4 inches for the bottom hem. Our Curtain Size Calculator includes built-in length adjustments for each style (sill, apron, floor) that account for standard hem allowances. However, if you're making your own curtains, we recommend adding an additional 2-3 inches to the final length to allow for adjustments. You can always hem extra fabric away, but you can't add fabric that's too short.