Curtain Size Lab Search

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Curtain Length Calculator

Calculate curtain drop for sill, apron, floor, break, and puddle endpoints. Results update as you type and all assumptions stay visible.

CURTAIN SIZE CALCULATOR

What are you measuring?

Desired curtain endpoint
72 in rod
Finished curtain width144 in total

72 in per panel × 2

Finished length90 in
Suggested rod72 in

Uses your 2× fullness and 6 in side extension. Floor length is an editable planning estimate; measure from the actual hanging point.

Open the detailed calculator

METHOD

How the calculation works

Rod length starts with the window width plus the entered extension at both sides. Total flat curtain width equals that working length multiplied by the selected fullness, then divides across the panel count.

Finished length starts from the entered window height and rod-above-window distance, then adds the selected endpoint distance. Because real sill-to-floor distance varies, the detailed calculation keeps that assumption visible.

Ready-made alternatives compare the calculated drop with common retail examples. They are options to investigate, not guarantees of fit.

Estimate, then verify

Measure the actual window and selected product. Manufacturer dimensions, heading systems, fabric behavior, and pattern matching can change the result. These tools do not determine hardware strength, fixings, or a guaranteed fit.

SOURCE NOTES

What this page is based on

Measurements here combine mathematical results with labeled commercial conventions and design recommendations. Disagreements are kept as ranges rather than averaged into a false standard.

  1. BETYDLIG/RÄCKA/HUGAD buying guide — Measure your windowIKEA · reviewed 2026-09-11

    Primary manufacturer guide: add at least 6 in each side, add 6 in above, and use 2–2.5× rod width for panel planning.

  2. MATILDA curtain product specificationsIKEA · reviewed 2026-09-11

    Manufacturer product guidance presents 1.5×, 2×, and 2.5× rod/track-width options for light through extra-full looks.

  3. Buying curtainsJohn Lewis & Partners · reviewed 2026-09-11

    Retailer/workroom guidance on pole extension, hanging references, sill/floor endpoints, ready-made metric ranges, and double fullness.