Curtain Fullness and Fabric Drop Planner
Estimate full-width fabric drops for equal curtain panels with entered fullness, hems, joining seams and straight vertical repeats.
YOUR CALCULATION
Result
—
Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Divide the desired flat width equally between panels. Determine whole fabric widths per panel after seams and side hems. Add header and bottom allowance to each drop, round up for straight pattern matching and total all drops.
Desired flat width=rail×fullness; net panel width=k×fabric width−2 seam×(k−1)−2 side hem
Worked example
A 2 m rail, fullness 2 and two panels require 2 m flat width per panel. With 1.4 m fabric and the example allowances, each panel uses two full widths. Four drops round to 2.56 m each; plus 0.20 m initial waste, total fabric is 10.44 m.
Assumptions and input details
This is a conservative full-width-drop layout. Excess width may be trimmed; partial-width offcuts are not shared between panels. Fullness and all allowances are entered choices, not recommendations for a heading style. Only straight vertical repeats are modeled; horizontal matching, half-drop patterns, lining, shrinkage, returns and overlaps require separate allowance. The untrimmed fullness is shown separately from the entered target.
References: Sailrite: curtain widths and vertical repeats
Unit definitions
Unit selection is independent of language. Each selector contains only units for its physical quantity. Calculations use defined base units internally.
Choose from 23 length definitions, including explicitly labelled regional measures. Area conversions square the length factor; geometric volumes cube it.
Regional measures are not interchangeable merely because their names look similar. This is a documented selection, not a claim to include every historical unit.
NIST measurement tables · Japanese traditional units · Mainland China and Hong Kong unit distinctions
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
Plan identical rectangular fabric pieces with seam allowances, shrinkage, selvages and optional 90-degree rotation.
Estimate full-height wallpaper drops and rolls with trim and straight pattern matching.
Find real length, drawing length or a scale ratio. Mix length units and compare linear, area and volume scale factors with a size diagram.
Reserved advertising space.