Curtain Size Calculator - Calculate Perfect Curtain Dimensions

Calculate ideal curtain width, length, and fabric requirements for perfect window treatments with accurate fullness ratios

Updated: November 2025 • Free Tool

Curtain Size Calculator

Actual window width

Actual window height

Above window frame

Curtain fullness

Length style

Panel count

Curtain Dimensions

Total Curtain Width
120"
Width Per Panel 60"
Curtain Length 78"
Rod Width 72"
Fabric Needed 10.8 yards
Hem Allowance 10"

What is a Curtain Size Calculator?

A Curtain Size Calculator is a free tool that helps you determine the perfect curtain dimensions for your windows. It calculates the ideal curtain width, length, and fabric requirements based on your window measurements, desired fullness, and style preferences.

This calculator works for:

  • New window treatments - Calculate curtain sizes for new homes or room renovations
  • Custom curtains - Determine fabric requirements for DIY or custom-made curtains
  • Ready-made curtains - Find the right size when shopping for pre-made curtains
  • Interior design projects - Plan window treatments for professional or personal design projects

For calculating room dimensions and space planning, check out our TV Viewing Distance Calculator to optimize furniture placement and viewing comfort in your living spaces.

Planning a home renovation budget? Use our Monthly Budget Calculator to allocate funds for curtains, furniture, and other home improvement expenses.

Shopping for curtains during sales? Our Percent Off Calculator helps you calculate discounts and final prices for home decor purchases.

How Curtain Size Calculator Works

The calculation uses these formulas:

Curtain Width = Window Width × Fullness Ratio
Curtain Length = Window Height + Rod Height + Style Adjustment
Fabric Needed = (Curtain Width × Curtain Length + Hem) ÷ 36

Where:

  • Window Width = Actual width of the window frame
  • Fullness Ratio = 1.5x to 3x for desired curtain fullness
  • Rod Height = Distance above window frame to mount rod (typically 4-6 inches)
  • Style Adjustment = Kiss floor (0"), puddle (1-2"), or hover (-0.5")
  • Hem Allowance = Additional fabric for top and bottom hems (typically 10 inches total)

Key Concepts Explained

Fullness Ratio

The multiplier applied to window width for proper draping. 2x is standard, 2.5-3x is luxurious.

Rod Placement

Mounting rods 4-6 inches above the window makes ceilings appear taller and windows larger.

Curtain Length

Kiss floor (just touching), puddle (1-2" on floor), or hover (0.5" above) for different styles.

Hem Allowance

Extra fabric needed for top and bottom hems, typically 4-6 inches each (10 inches total).

How to Use This Calculator

1

Measure Window

Measure actual window width and height in inches (e.g., 60" × 72")

2

Set Rod Height

Enter how high above window to mount rod (typically 4-6")

3

Choose Fullness

Select desired fullness ratio (2x standard, 2.5-3x luxurious)

4

Select Style

Choose curtain length style (kiss, puddle, or hover)

5

Set Panel Count

Choose number of curtain panels (typically 2 panels)

6

Get Results

View curtain dimensions and fabric requirements instantly

Benefits of Using This Calculator

  • Accurate Measurements: Get precise curtain dimensions for perfect window coverage and professional appearance.
  • Fabric Estimation: Calculate exact fabric requirements to avoid buying too much or too little material.
  • Cost Savings: Prevent costly mistakes by ordering the right size curtains the first time.
  • Professional Results: Achieve designer-quality window treatments with proper fullness and length ratios.
  • Multiple Styles: Compare different curtain styles and fullness options to find your perfect look.

Factors That Affect Your Results

1. Window Type

Bay windows, corner windows, and sliding doors require different measurements and panel configurations.

2. Fabric Type

Heavier fabrics like velvet need less fullness (1.5-2x), while sheer fabrics look best with more fullness (2.5-3x).

3. Ceiling Height

Higher ceilings allow for more dramatic rod placement and longer curtain lengths for visual impact.

4. Room Style

Modern rooms often use minimal fullness and clean lines, while traditional rooms favor fuller, more gathered curtains.

Curtain Size Calculator - Free online tool to calculate perfect curtain width, length, and fabric requirements with fullness ratios
Professional curtain size calculator interface showing input fields for window dimensions, rod height, fullness ratio, and curtain style. Provides instant calculations for curtain width, length, fabric needed, and panel dimensions with mobile-friendly design.

Frequently Asked Questions (FAQ)

Q: How much wider should curtains be than the window?

A: Curtains should be 1.5 to 3 times wider than the window for proper fullness. For a standard gathered look, use 2 times the window width. For a fuller, more luxurious appearance, use 2.5 to 3 times the width.

Q: How long should curtains be?

A: Curtains should either just touch the floor (kiss length), puddle slightly on the floor (1-2 inches), or hover 0.5 inches above the floor. For a modern look, curtains that just kiss the floor are most popular. Avoid curtains that hang several inches above the floor as they can make the room look shorter.

Q: How high should I hang curtain rods?

A: Hang curtain rods 4-6 inches above the window frame, or even higher near the ceiling for a dramatic effect. Mounting rods higher makes ceilings appear taller and windows larger. The rod should extend 3-6 inches beyond each side of the window frame.

Q: How do I calculate curtain fabric needed?

A: Calculate curtain fabric by multiplying your window width by your desired fullness ratio (typically 2x), then add the finished length plus hem allowances (usually 8-12 inches total for top and bottom hems). Don't forget to account for pattern repeats if using patterned fabric.