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Eyelet Curtain Calculator — Eyelets & Fabric
Calculate eyelet spacing, heading fabric and ring quantities.
How We Calculate This
Eyelet curtains typically use 2× fullness (the standard for the eyelet heading), though 1.5× and 2.5× are selectable. The number of eyelets is calculated from the curtain width and spacing, always rounded to an even number so the leading and trailing edges both fold back towards the window.
The formula
Total width = Pole width × fullness (default 2× for eyelet)
Eyelets per curtain = round(Width per curtain ÷ Spacing) (rounded up to an even number)
Heading fold = (Above eyelet + Eyelet radius + 2cm) × 2
Cut drop = Curtain drop + Hem + Heading fold
If you enter a pattern repeat, the cut drop is rounded up to the next whole repeat so the motif lines up across each fabric width.
Frequently Asked Questions
Eyelets should be evenly spaced 12-18cm apart. Each curtain must have an even number of eyelets so the leading edge folds towards the window. This creates the signature wave fold of eyelet curtains.
Eyelet rings are sized by their inner-hole diameter, which must be at least 10mm larger than the pole so the curtain slides freely. The two standard UK sizes are 40mm and 50mm: a 40mm ring suits a 28mm pole, and a 50mm ring suits a 35mm pole (a 66mm ring is also made for 50mm poles). Note that 28mm and 35mm refer to the pole diameter, not the eyelet.
Allow 2-4cm of fabric above the eyelet ring for a stand-up heading. The heading folds over so you need double this plus the eyelet depth. This is included in the cut drop calculation.
You can use either. Eyelet tape (header tape with pre-spaced holes) is easier for beginners. Loose clip-together eyelets allow custom spacing. Both need a stiffened heading — use buckram or header tape interfacing.
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Last updated: February 2026
All calculations are estimates. Always verify quantities before cutting or purchasing fabric.