Curtain Interlining Yardage Calculator

Plan interlining cuts before sewing curtains for patios. Match widths, allowances, and lining behavior easily. Get yardage, waste, and roll estimates with one submit.

Calculator Inputs

All length fields follow this unit.
Choose yards or meters for results.
Pairs are typically 2 panels.
Visible width after hanging.
Top to finished hem.
Common: 2.0 for pleated drapery.
Typical rolls are 54 wide.
Allow for selvedges and trimming.
Take-up accounts for loft and quilting behavior.
Interlining supports hems on both sides.
Top turn and heading depth.
Deeper hems improve drape and weight.
Pre-steam or pre-shrink to reduce surprises.
Use 0 for solids or no matching.
Rounds cut drop to the next full repeat.
Covers small errors and trimming.
Helps estimate how many rolls to buy.
Used only when roll length is filled.
Reset
After you calculate, the result appears above this form.

Example Data Table

Scenario Width Drop Panels Fullness Interlining width Waste Estimated interlining
Patio door, standard 50 in 84 in 2 2.0 54 in 5% ~ 6.6 yd
Garden bay, thermal 60 in 96 in 2 2.5 54 in 7% ~ 10.9 yd
Kitchen nook, short 40 in 54 in 2 2.0 54 in 5% ~ 4.1 yd
These examples are approximate. Your fabric width, hems, and shrinkage can change results.

Formula Used

This calculator treats interlining as a roll fabric. It estimates how many full widths are needed, then multiplies by the adjusted cut drop.
  1. Flat width per panel = (Finished width × Fullness) + (2 × Side hem each)
  2. Usable width = Interlining width − Usable width deduction
  3. Widths per panel = ceil(Flat width per panel ÷ Usable width)
  4. Cut drop = Finished drop + Header allowance + Bottom hem (then optional pattern rounding)
  5. Adjusted drop = Cut drop × (1 + (Shrinkage% + Take‑up%) ÷ 100)
  6. Total interlining = Adjusted drop × Total widths
  7. With waste = Total interlining × (1 + Extra waste% ÷ 100)

How to Use This Calculator

  • Measure each panel’s finished width and finished drop after installation planning.
  • Choose a fullness factor that matches your heading style and desired pleats.
  • Enter your interlining roll width and a realistic usable deduction for trimming.
  • Set hems and header allowances based on your sewing method and hardware.
  • Add shrinkage if you will steam, pre-shrink, or if the interlining is lofted.
  • Turn on repeat matching only when you must align patterns by length.
  • Use the waste percent to cover mistakes, squaring, and sample cuts.
  • Press Calculate; download a CSV or PDF for your cutting plan.

Related Calculators

Curtain panel quantity calculatorCurtain fabric yardage calculatorCurtain rod bracket spacingCurtain lining yardage calculatorCurtain hem allowance calculatorCurtain puddle length calculatorCurtain tieback placement calculatorCurtain tieback length calculatorCurtain width per windowCurtain drop length calculator

Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.