How deep should a pelmet be?

A pelmet should be approximately 1/6 of the curtain drop. For 210cm curtains, a 35cm pelmet works well. Minimum depth is usually 25cm to hide the curtain track and heading. Shaped pelmets may be deeper at the centre.

How far should a pelmet extend beyond the window?

The pelmet board should extend 10-15cm beyond each side of the curtain track. The return (depth from wall) should be deep enough to clear the curtains when drawn — typically 12-18cm.

What is the difference between a padded and buckram pelmet?

A padded pelmet is soft with wadding behind the fabric for a plump look. A buckram pelmet uses stiffened buckram for a rigid, structured shape. Buckram pelmets can be cut into decorative shaped edges.

Do I need a pelmet board?

Yes, a pelmet board is essential. Use 15-18mm MDF or plywood. The board mounts above the window with angle brackets. The pelmet fabric is attached to the board with Velcro for easy removal and cleaning.

SewCalcs

Pelmet Calculator — Fabric & Board Dimensions

Calculate fabric and board dimensions for pelmets and valances.

Window Width

Pelmet Depth

Return Depth

Depth from wall

Pelmet Style

Fabric Price (optional)

How We Calculate This

Pelmet dimensions are calculated from the window width plus returns. The fabric needs to wrap around or gather depending on style.

The formula

Board length = Window width + (Return depth × 2)

Padded/Buckram: Fabric width = Board + 10cm, Height = Depth × 2 + 10cm

Gathered: Fabric width = Board × 2.5, Height = Depth + 20cm

Frequently Asked Questions

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Last updated: February 2026

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