How Our Online Calculator Works
Our calculator estimates fabric for curtains, blinds, and accessories by factoring in fullness, pattern repeats, and finishing allowances—so you can order confidently and achieve a professional finish.
Where to Find & How to Use the Calculator
- Open any fabric product page on our website—every fabric includes the calculator.
- Enter your measurements and choose heading style, lining, and any options.
- Review the estimate: you can either note the calculated fabric quantity for your records, or click Add Basket.
- If selected, the calculator will also add your chosen lining(s) to the basket automatically.
You can repeat the process for multiple windows, adjusting headings, fullness, or lining as required.
Key Parameters We Build Into Your Quote
| Heading | Fullness | Hem Allowance |
|---|---|---|
| Pencil Pleats | 2.0× | 25 cm |
| Double Pleats | 2.2× | 38 cm |
| Eyelets | 2.0× | 38 cm |
| Wave | 2.3× | 38 cm |
- We calculate the number of full pattern repeats required for each drop.
- We add one extra full repeat to allow precise pattern placement and matching.
Curtains
- Fullness and hem allowances as shown in the table.
- Full-drop calculation includes required full pattern repeats plus one additional repeat for design positioning.
- Fabric widths and joins are optimised to achieve a balanced pair.
Blinds & Accessories
- Blinds: Includes standard 25cm workroom turnings/hemming and, where applicable, one full repeat for design placement.
- Cushions: We allow an additional 20 cm per cushion to cover piping if piping is requested.
- Heading Tape / Buckram: We allow 1.5 m per fabric width for curtains.
Important Notice
Our calculator is a guide only. Every maker/workroom may use different formulas and allowances. While we take great care with our estimates, Simon Philip Interiors cannot be held responsible for shortages or excess if our results differ from your own calculations. Once fabric has been cut it cannot be returned. Please double-check measurements and confirm with your maker before ordering.
