Curtain Calculator

Curtain Fabric & Track Calculator

Use this calculator to estimate the amount of fabric, lining, and the ideal track or pole length needed for your custom curtains. Accurate measurements are key to beautiful results!

Measure the width of your window recess. For track/pole, measure the existing track/pole or add 20-30cm to the window width.

Measure from where your track/pole will sit to your desired finished length (e.g., sill, below sill, or floor).

Standard fabric widths are often 137cm, 140cm, or 150cm. Check your chosen fabric's specifications.

Enter 0 if your fabric has no pattern repeat. If it does, this ensures drops are cut to match the pattern.

Common fullness factors: 1.5x (minimal), 2.0x (standard), 2.5x (generous), 3.0x (very full, for sheer/light fabrics).

Extra fabric for the top hem, usually 10-20cm depending on heading type.

Extra fabric for the bottom hem, usually 15-25cm for a good weight and drape.

Your Curtain Requirements:

Number of Fabric Widths:

Total Main Fabric Length:

Total Lining Fabric Length:

Recommended Track/Pole Length:

Always add a little extra for safety, especially with patterned fabrics. Consider consulting a professional for complex designs.

Understanding Your Curtain Fabric & Track Needs

Creating custom curtains can transform a room, adding warmth, style, and privacy. However, accurately calculating the amount of fabric, lining, and the correct track or pole length is crucial for a professional finish and to avoid costly mistakes. This guide and calculator will help you demystify the process.

Key Measurements and Inputs Explained:

1. Window Width (cm)

This is the fundamental measurement. For curtains, you generally want your track or pole to extend beyond the window recess to allow the curtains to be drawn back fully, letting in maximum light. A common rule of thumb is to add 20-30 cm to the total width of your window recess (10-15 cm on each side). If you already have a track or pole installed, measure its full length.

2. Finished Curtain Drop (cm)

The drop is the final length of your curtain. Measure from the top of where your track or pole will sit down to your desired finish point. This could be:

• Sill Length: Just touching or hovering slightly above the windowsill.
• Below Sill: Extending 10-15 cm below the windowsill.
• Floor Length: Just touching or hovering 1-2 cm above the floor.
• Puddled: Extending 15-30 cm or more onto the floor for a luxurious, relaxed look.

Always measure in at least three places across the width of your window and use the shortest measurement to avoid curtains dragging, or the longest if you want to ensure full coverage.

3. Fabric Roll Width (cm)

Fabric is sold in rolls of standard widths. Common widths include 137 cm, 140 cm, and 150 cm. It's essential to know the exact width of your chosen fabric, as this directly impacts how many "widths" of fabric you'll need to join together to achieve the desired curtain fullness.

4. Pattern Repeat (cm)

If your fabric has a pattern, it will likely have a "pattern repeat" measurement. This is the vertical distance before the pattern starts again. When cutting multiple drops of patterned fabric, you need to account for this repeat to ensure the pattern matches seamlessly across all panels. The calculator adds extra length to each drop to allow for this matching, so you don't end up with misaligned designs.

5. Desired Fullness Factor

The fullness factor determines how gathered or "full" your curtains will look when drawn. It's a multiplier of your track/pole width:

• 1.5x (Minimal Fullness): Suitable for very stiff fabrics or a contemporary, flat look.
• 2.0x (Standard Fullness): The most common choice, offering a good balance of drape and fullness.
• 2.5x (Generous Fullness): Ideal for lighter fabrics, sheers, or if you want a more luxurious, abundant look.
• 3.0x (Maximum Fullness): Often used for very lightweight or sheer fabrics to create a rich, flowing effect.

Higher fullness factors require more fabric.

6. Top Hem Allowance (cm)

This is the extra fabric needed at the top of your curtain for the heading (e.g., pencil pleat, pinch pleat, eyelet). A typical allowance is 10-20 cm, depending on the heading tape or construction method used.

7. Bottom Hem Allowance (cm)

The bottom hem provides weight and a neat finish to your curtains. A generous bottom hem (15-25 cm) helps the curtains hang well. The calculator includes this extra length in your total fabric requirement.

Understanding the Calculator's Outputs:

Number of Fabric Widths

This tells you how many full widths of your chosen fabric you'll need to join together to achieve the desired fullness for your window. For a pair of curtains, this number will be divided between the two panels.

Total Main Fabric Length (meters)

This is the total amount of main curtain fabric you need to purchase, taking into account the number of widths, the finished drop, and all allowances (hems, pattern repeat). It's always wise to add a small contingency (e.g., 0.5 to 1 meter) to this total, especially with patterned fabrics, just in case of cutting errors or future adjustments.

Total Lining Fabric Length (meters)

Lining adds body, protects your main fabric from sun damage, and can improve insulation and light blocking. The lining length is calculated similarly to the main fabric but typically does not require pattern matching, so its cut length per drop might be slightly less if your main fabric has a large pattern repeat.

Recommended Track/Pole Length (meters)

This output provides an ideal length for your curtain track or pole, usually calculated to be approximately 20% wider than your window recess. This allows your curtains to be drawn back fully, clearing the window and maximizing natural light.

Example Scenario:

Let's say you have a window that is 150 cm wide and you want your curtains to drop 220 cm to the floor. You've chosen a fabric that is 140 cm wide with a 60 cm pattern repeat, and you desire standard (2.0x) fullness. You'll use a 15 cm top hem and a 20 cm bottom hem.

• Window Width: 150 cm
• Finished Curtain Drop: 220 cm
• Fabric Roll Width: 140 cm
• Pattern Repeat: 60 cm
• Fullness Factor: 2.0
• Top Hem Allowance: 15 cm
• Bottom Hem Allowance: 20 cm

Based on these inputs, the calculator would determine:

• Desired Finished Curtain Width: 150 cm * 2.0 = 300 cm
• Number of Fabric Widths: Ceiling(300 cm / 140 cm) = 3 widths
• Base Cut Length per Drop: 220 cm + 15 cm + 20 cm = 255 cm
• Pattern Matched Cut Length per Drop: Ceiling(255 cm / 60 cm) * 60 cm = 5 * 60 cm = 300 cm
• Total Main Fabric Length: 3 widths * 300 cm/width = 900 cm = 9.0 meters
• Total Lining Fabric Length: 3 widths * 255 cm/width = 765 cm = 7.65 meters
• Recommended Track/Pole Length: 150 cm * 1.2 = 180 cm = 1.8 meters

This means you would need to purchase 9.0 meters of your main fabric and 7.65 meters of lining fabric, and your track or pole should be around 1.8 meters long.

Important Considerations:

• Fabric Type: Heavy fabrics might require less fullness, while very light or sheer fabrics often look better with more.
• Heading Style: Different heading styles (e.g., eyelets, tab tops, pencil pleats, pinch pleats) can affect the required top hem allowance and how the fullness is distributed.
• Professional Advice: For complex window treatments, bay windows, or if you're unsure, always consult with a professional curtain maker or interior designer.
• Seam Allowances: While not explicitly an input, remember that when joining fabric widths, you'll need seam allowances (typically 1.5-2.5 cm per seam). The calculator provides the total fabric needed, assuming these are accounted for in the overall width calculation.

By using this calculator and understanding the principles behind curtain measurements, you're well on your way to creating beautiful, custom window dressings for your home!