This Roman shade size calculator helps homeowners, renters, decorators, and sewing workrooms turn window measurements into a practical planning estimate before ordering fabric, lining, hardware, or ready-made shades. It focuses on the questions that usually cause mistakes: whether the shade should mount inside or outside the frame, how much side overlap is needed for privacy, how much extra height is needed above the trim, and how pattern repeat changes yardage.
The worksheet uses opening width, opening height, mount type, side overlap, top allowance, bottom allowance, inside deduction, fabric width, vertical repeat, hem allowance, lining choice, waste percentage, and the number of matching shades. From those inputs it estimates finished shade width, finished drop, cut width, cut drop, face-fabric yardage, rough lining yardage, and notes about privacy gaps, narrow openings, and vendor confirmation.
For an inside mount, the calculator starts with the narrowest clear opening width and subtracts a small planning deduction so the shade can move without rubbing. You still need to check depth, squareness, locks, cranks, tile, and trim buildup because those details decide whether an inside mount is realistic. For an outside mount, it adds overlap on both sides, height above the opening, and bottom coverage so the fabric can hide light gaps and make the raised shade look intentional.
Roman shade yardage depends on usable fabric width, finished drop, hems, seams, repeat matching, lining, and waste. The calculator rounds the required number of fabric widths upward, adds repeat allowance when a vertical repeat is entered, multiplies by the number of shades, and adds a waste factor. The lining estimate is intentionally rough because blackout lining, interlining, railroaded fabric, seam placement, and workroom methods can change the final order.
Measure width at the top, middle, and bottom, then measure height at the left, center, and right. Photograph obstructions, record inside depth, choose cord-safe or cordless hardware that complies with current safety rules, and confirm whether the vendor or workroom wants finished dimensions or opening dimensions. Keep a labeled worksheet for each window so multiple shades are not mixed during ordering or installation.
Do not measure only one spot on an older window. Painted trim, out-of-square jambs, bowed sills, and replacement window inserts can make the top, middle, and bottom widths different. Do not assume a decorative fabric width is the same as the usable cut width, because selvage, printed borders, railroaded orientation, and pattern centering may reduce what can actually be used. Do not order several shades from memory; label every opening and keep the room name, window position, and mount type together.
Use the finished width and finished drop as a planning conversation with the shade vendor or workroom, not as an automatic purchase order. If the supplier asks for opening dimensions, give the raw measurements and explain the mount type instead of sending the calculator's deducted size. If the supplier asks for finished dimensions, compare the calculator result with their required deduction, return, bracket, and clearance rules. When in doubt, ask the person making or supplying the shade to sign off before cutting fabric.
Should every shade in one room be the same width? Sometimes yes for visual symmetry, but only if the windows and trim can support the same finished size without rubbing or leaving gaps. Does blackout lining change sizing? It can increase thickness and stack height, so check hardware capacity and whether the raised shade blocks more glass. Can this estimate replace installer measurements? No. Installer measurements are still important when drilling into tile, masonry, plaster, or rental walls, or when child-safe hardware placement is required.
This site provides general measurement planning only. It is not a child-safety certification, cord-safety guide, fire-rating recommendation, sewing pattern, installation service, structural assessment, or guarantee that a shade will fit. Final dimensions should follow your fabric supplier, workroom, hardware manufacturer, installer, lease rules, and local safety requirements.
Reserved future ad placement only. No live ad code, no active ad unit, no product referral URL, no email collection, and no contact form is enabled.