How far should a curtain track extend beyond the window?

Extend 12-20cm beyond each side of the window frame. This is the stack-back space where curtains sit when fully open, allowing maximum light into the room. Heavier fabrics need more stack-back.

How many brackets does a curtain track need?

Place a bracket at each end and then space them every 50-60cm along the track. Heavy curtains or metal poles may need brackets every 40-50cm. Always place a bracket close to where curtains meet in the centre.

What are curtain track returns?

Returns are the parts of the track that bend back towards the wall at each end. They prevent light gaps at the sides and give a finished look. Returns are typically 10-15cm deep, matching the bracket projection.

Should I choose a track or pole?

Tracks are discreet, work with all heading types, and are ideal for bay windows. Poles are decorative and suit eyelet, tab top, and ring curtains. Tracks are better for heavy curtains as they distribute weight evenly.

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Curtain Track Calculator — Track & Pole Length

Work out curtain track or pole length for your windows.

Window Width

Width of window frame

Stack-Back Each Side

Extension beyond each side so curtains clear the glass when open (15–25 cm typical)

Mount TypeWall/ceiling fix extends beyond the window; recess fits inside the opening (no stack-back)

Include Returns

Track bends back to the wall at each end

Return Depth

Distance the track curves back to the wall — usually matches the bracket projection (~10–15 cm)

How We Calculate This

For a wall or ceiling mount, track length is the window width plus stack-back allowance on each side, so the open curtains clear the glass. Returns add extra length for the track to curve back to the wall. For an inside-recess mount the track simply fits the opening, so there is no stack-back, returns or overlap — the track length equals the window width.

The formula

Track length (wall/ceiling) = Window width + (Stack-back × 2)

Track length (recess) = Window width

With returns = Track length + (Return depth × 2)

Brackets = ceil(Track length ÷ bracket spacing) + 1

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always verify quantities before cutting or purchasing fabric.