Tools directoryimprovement

Curtain size calculator

How wide and long should the finished curtains be?

Before you startMeasure the window opening and decide where the rod and curtain bottom will sit.

Step 1

Add your measurements

Get total finished curtain width, rod width, and finished drop.

Example numbers are loaded

Replace each example with what you measured. The example result on the right updates as you type.

Measure the window and rodMeasure the visible opening before adding rod extensions.

Window widthcmMeasure the visible window opening from side to side.Window heightcmMeasure the visible opening from top to bottom.Rod extension each sidecmEnter how far the rod will extend past the window on each side.Rod above windowcmMeasure from the top of the window to the planned rod position.Drop below windowcmMeasure how far the curtain should continue below the window.

Choose the fullnessMore fullness creates deeper folds and requires more fabric.

Fullness multiplierChoose how gathered the closed curtains should look.

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Example resultLooks good on paper

Target 440 cm of total finished width

Split the finished width across the number of panels and confirm construction allowances.

Change the sample measurements to turn this into your estimate.

Rod width: 220 cm
Total finished width: 440 cm
Finished drop: 175 cm

Proportional planning schematic - verify all dimensions on site.

Before you buy or start work

Measure at several points.
Choose the final rod and heading first.
Ask the workroom for raw fabric yardage.

Method

What this result assumes

Fullness is applied to total rod width.

The calculation returns finished fabric dimensions, not raw cutting lengths.

Limitations

What it cannot confirm

Heading style, repeat, hems, seams, floor level, and fabric shrinkage require workroom confirmation.

This is a planning estimate, not a building-code, safety, installation, or delivery guarantee.

Confirm product-specific requirements with the manufacturer, installer, retailer, or qualified trade.

Formula 1.0.0Reviewed 2026-07-13General planning assumptions

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