Curtain Fabric Calculator
Calculate curtain fabric yardage from covered width, finished drop, fullness, and fabric width so you can compare panel count, repeat-adjusted cut length, and a safer buy quantity before ordering drapery fabric.
Curtain Inputs
Curtain Fabric Result
Current Calculation
Planning Notes
Use Scenarios
Estimate a buy quantity before ordering drapery fabric
Start from the covered width and finished drop you actually want, then convert fullness, hems, and heading depth into a yardage plan before you buy curtain fabric online or from a workroom supplier.
Compare standard-width and wide-width fabric choices
Large windows and patio doors often change materially when you switch from a 54-inch bolt to a 118-inch drapery width, so this calculator helps you see whether fewer seams justify the higher price per yard.
Plan repeat-heavy or pleated headings more conservatively
Use it when pattern repeat, pinch pleats, or extra break length could move the job beyond a simple flat-panel estimate. If you already know the finished panel rectangles instead of the coverage width, move to the Fabric Yardage Calculator.
Formula Explanation
1) Build the finished width to cover
Finished width at fullness = covered width x fullness ratio
This converts the width you want the curtains to span into the total finished fabric width needed after gathering or pleating.
2) Round the width into whole panels
Panels = ceil(finished width at fullness / fabric width)
Fabric is bought in full widths, so the panel count always rounds up to the next whole width even when you are only slightly over the bolt width.
3) Add length allowances before the repeat step
Base cut length = finished drop + extra drop + hem + header
The vertical cut starts with the finished drop, then adds break or clearance adjustment plus the allowance needed to turn the hem and form the chosen heading.
4) Round each panel for repeat and shopping buffer
Repeat-adjusted cut = ceil(base cut / repeat) x repeat; buy quantity = exact cut x (1 + buffer)
A repeat rounds every panel to the next full motif cycle, and the shopping buffer keeps extra yardage available for recuts, squaring, and minor workroom loss.
How to Read the Result
Recommended buy quantity
Use the recommended buy quantity for purchasing. It starts from the exact cut amount and then adds a small shopping buffer so the order is less exposed to cutting loss or a small measuring mistake.
Panels and cut length
Panel count tells you how many full fabric widths are being used, while cut length per panel shows the vertical length each drop needs after hems, heading depth, and repeat adjustment.
When to revise the inputs
Recheck the width if the rod extends beyond the window, recheck the drop if you want floor clearance or puddle, and use a more conservative repeat plan for half-drop or engineered motifs.
Example Cases
Case 1: Standard living-room pair
Inputs
- Covered width: 96 in
- Finished drop: 84 in
- Heading style: Rod Pocket
- Fullness: 2x on 54 in fabric
- Repeat + allowances: 0 in repeat, 8 in hem, 8 in header
Computed Results
- Recommended buy: 12.5 yd (11.5 m)
- Exact cut amount: 11.25 yd
- Panels: 4
- Cut length per panel: 100 in
- Repeat added: 0 in
Interpretation
This is a straightforward standard-width drapery job. The panel count rises because 192 inches of finished width at fullness cannot be covered by only three 54-inch widths.
Decision Hint
If four standard-width panels feel seam-heavy or expensive, compare the same width and drop on a wide-width fabric before ordering.
Case 2: Wide-width patio-door drapery
Inputs
- Covered width: 120 in
- Finished drop: 96 in
- Heading style: Grommet / Eyelet
- Fullness: 2.2x on 118 in fabric
- Repeat + allowances: 0 in repeat, 8 in hem, 6 in header
Computed Results
- Recommended buy: 10.25 yd (9.5 m)
- Exact cut amount: 9.25 yd
- Panels: 3
- Cut length per panel: 109 in
- Repeat added: 0 in
Interpretation
The wide-width bolt reduces the seam count on a large opening, and the small negative adjustment keeps the finished curtain just off the floor for easier sliding and cleaning.
Decision Hint
Use this kind of result to judge whether fewer seams, cleaner stack-back, and easier fabrication are worth choosing a wide-width plan on a large opening.
Case 3: Patterned pinch-pleat formal drapes
Inputs
- Covered width: 72 in
- Finished drop: 108 in
- Heading style: Pinch Pleat
- Fullness: 2.5x on 54 in fabric
- Repeat + allowances: 27 in repeat, 8 in hem, 8 in header
Computed Results
- Recommended buy: 16.5 yd (15.25 m)
- Exact cut amount: 15 yd
- Panels: 4
- Cut length per panel: 135 in
- Repeat added: 9 in
Interpretation
This is where repeat-heavy formal drapery becomes materially different from a simple plain-fabric estimate. The repeat step adds extra length to every panel, not just to the first one.
Decision Hint
Use a more conservative workroom review if the design is half-drop, motif-centered, or engineered to land at a specific point in the heading.
Boundary Conditions
Sources & References
- British Institute of Interior Design - How to Survey Windows and Calculate Fabric (PDF)Used for survey terminology, drop measurement context, heading allowances, and the repeat-aware fabric-calculation sequence for custom window treatments.
- Spotlight - Curtain Fabric Calculation Project (PDF)Used as a practical worked example for curtain meterage, especially the order of width, drop, hem, and repeat steps in a consumer-facing drapery workflow.
- Sailrite - How to Measure for Window TreatmentsKept as a supporting measurement reference after SERP review because it explains covered width, fullness guidance, and floor clearance choices in the same practical framing users often need before entering calculator inputs.