Calculator
Formula used
This estimator treats each panel as a set of full fabric widths that are seamed together. It calculates the needed cut width from finished coverage, fullness, and side hems.
- Finished total width = window width + overlap + 2 × returns
- Finished panel width = finished total width ÷ panels
- Cut panel width = (finished panel width × fullness) + 2 × side hem allowance
- Usable fabric width = fabric width − 2 × selvage unusable
- Widths per panel = ceil(cut panel width ÷ usable fabric width)
- Raw cut length = drop + top allowance + bottom hem + puddle + style extras
- If pattern repeat > 0, adjusted length = ceil(raw cut length ÷ repeat) × repeat
- Length with shrink = adjusted length × (1 + shrinkage%)
- Total inches = length with shrink × widths per panel × panels
- Total yards = total inches × (1 + waste%) ÷ 36
For outdoor garden curtains, you may prefer higher fullness and a heavier bottom hem to resist wind and keep the edge straight.
How to use this calculator
- Measure width and drop where the outdoor curtain will hang.
- Pick the number of panels and a fullness multiplier.
- Enter fabric width and realistic hem allowances.
- Add pattern repeat if you need print matching.
- Include shrinkage for pre-washed or sun-exposed fabric.
- Click Calculate, then export your cut list.
Measure for outdoor mounting points
For garden curtains, measure the span between posts or wall brackets where the rod will sit. Record the drop from rod height to your target end point, such as deck boards, patio pavers, or a planter ledge. Add return allowances when the fabric will wrap back to a post for better wind control and privacy.
Convert coverage to panel cut width
The calculator converts finished coverage into a practical cut width by applying fullness and side hem allowances. A fullness multiplier of 2.0 is common for outdoor spaces because it softens harsh sunlight while still moving freely. Higher fullness can improve privacy, but it increases seam count and fabric consumption.
Plan cut length with hems and style
Outdoor panels often use deeper bottom hems to keep edges straight in breezes. The tool adds top allowance, bottom hem, puddle length, and a style allowance for common header types. If you are adding weights, pocket hems, or trim, include them as extra style allowance so the cut length remains realistic.
Account for repeats, shrinkage, and waste
Printed fabrics may require vertical repeat matching, especially when panels meet at a center opening. The calculator rounds the cut length up to the next full repeat, then applies shrinkage and a contingency factor. Use shrinkage values based on prewashing or exposure expectations, since sun and moisture can change hand and length.
Use outputs to buy and cut efficiently
Your results include widths per panel, cut width, and cut length, which together form a simple cutting plan. When shopping, compare usable width after selvage to reduce unnecessary seaming. If lining is enabled, the tool estimates lining yardage separately so you can balance shade protection, durability, and budget for the full garden installation. Before cutting, square the grain, label each width, and keep pattern direction consistent. For long runs, order an extra half yard per fabric type to cover end-of-bolt variation and future repairs after storms or heavy sun.
FAQs
Most patio and pergola curtains look best at 1.8 to 2.2 fullness. Higher fullness improves privacy and light filtering, but it increases seams and yardage. Use lower fullness where wind and tangling are concerns.
Narrower fabric requires more full widths to reach your cut width, which multiplies yardage. Checking usable width after selvage is important. A slightly wider fabric can reduce seams and total length purchased.
If a print has a vertical repeat, panels often need extra length so motifs align from one panel to the next. The calculator rounds cut length up to a full repeat, which can add significant yardage on tall drops.
Yes, especially if you plan to prewash or if the fabric will see moisture and heat. Add shrinkage based on your material tests or supplier guidance. For many outdoor fabrics, 1–3% is a practical starting point.
Lining can improve UV resistance, provide shade, and extend fabric life. It also adds weight, which helps panels hang straight. Use the optional lining estimate to plan a separate purchase for lining material.
Confirm your measurements, keep hems consistent, and plan seam placements before cutting. If possible, choose a fabric width that minimizes the number of widths per panel. Add only a small contingency unless your print matching is complex.
Example data table
| Scenario | Key inputs | Estimated main fabric |
|---|---|---|
| Patio shade pair | 72 in width, 84 in drop, 2 panels, fullness 2.0, 54 in fabric | ~7.0–9.0 yd (depends on hems/repeat) |
| Pergola privacy set | 120 in width, 96 in drop, 4 panels, fullness 2.2, 60 in fabric | ~16–22 yd (add lining for sun) |
| Greenhouse draft block | 48 in width, 72 in drop, 2 panels, fullness 1.5, 54 in fabric | ~4–6 yd with a heavier hem |