How to Use Curtain Panel Calculator
The Curtain Panel Calculator takes window dimensions and outputs the number of curtain panels and yardage needed.
- Enter Window Width — Measure the inside of the window frame or the curtain rod span.
- Enter Curtain Drop — Length from rod to where you want the hem.
- Choose Fullness — 1.5×, 2×, 2.5×, or 3× depending on style.
- Enter Fabric Width — Bolt width of the curtain fabric you plan to buy.
- Read the Result — Panel count, total fabric width, total fabric length, and yardage / meterage.
Formula & Theory — Curtain Panel Calculator
total_panel_width = window_width × fullness
panels = ceil(total_panel_width ÷ fabric_width)
drop_total = drop + hem_allowance + header_allowance
fabric_length = panels × drop_total| Symbol | Meaning |
|---|---|
| window_width | Window or rod width |
| fullness | Ratio (1.5–3.0) |
| fabric_width | Bolt width of fabric |
| drop | Length from rod to hem |
| hem_allowance | Extra for bottom hem |
| header_allowance | Extra for top header / rod pocket |
Fullness Guide
1.5× light, modern, sheer panels
2.0× standard / most common
2.5× full, traditional living room
3.0× luxurious, theatre or dining roomUse Cases for Curtain Panel Calculator
- Home Sewing Projects — Make custom drapes for any window.
- Interior Designers — Quote yardage to fabric suppliers fast.
- Theatre & Stage — Plan stage curtains with high fullness ratios.
- Hotels & B&Bs — Standardize curtain orders across multiple rooms.
- DIY Backdrops — Quickly compute fabric for photography or event backdrops.
The Curtain Panel Calculator prevents costly buy-too-little or buy-too-much trips to the fabric store.