1. What is Blackout Curtain Size?

The blackout curtain size is the total width needed for curtains to effectively block light from a window. It includes the window width plus additional overlap on each side to prevent light leakage.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• Window Width — The actual width of your window
• Light Block Overlap — The additional width needed on each side to block light

Explanation: The formula accounts for the need to have extra curtain material extending beyond the window frame on both sides to effectively block light.

3. Importance of Proper Blackout Size

Details: Correct blackout curtain sizing is essential for complete light blocking, proper installation, and aesthetic appearance. Undersized curtains allow light leaks while oversized curtains may look bulky.

4. Using the Calculator

Tips: Measure your window width accurately in inches. The light block overlap is typically 4-8 inches per side but may vary based on your needs. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: How much overlap do I need for complete blackout?
A: Typically 4-8 inches per side, but more may be needed for very bright rooms or if mounting inside the window frame.

Q2: Should I measure the window frame or glass area?
A: Measure the entire window frame (or the area you want to cover) unless mounting inside the frame.

Q3: Does this account for curtain fullness?
A: No, this calculates the flat width needed. For pleated or gathered curtains, you'll need additional width.

Q4: What if my window is very wide?
A: For windows wider than standard curtain panels (usually 50-54 inches), you'll need multiple panels with proper overlap between them.

Q5: Should I round up the final size?
A: Yes, round up to the nearest standard curtain size available (typically in even inch increments).