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Gather and Pleat Calculator: Fullness Ratio to Fabric Width

Convert a finished width and fullness ratio into gathered or pleated source width, take-up, and complete pleat repeats.

Your measurements

Use one unit for every dimension in this form.

Select the shaping style.

Width after gathering or pleating.

Source width divided by finished width.

Finished repeat width; ignored for gathers.

Pleats and gathers result

Source width
80.00 in
Take-up
40.00 in
Complete repeats
Not applicable
Fullness planA scaled planning diagram. Use the matching text result and cut list for exact dimensions.gather2× fullness
Fullness plan. The drawing is scaled for comparison; written dimensions control.

Formula

Source width equals finished width times fullness ratio; pleat repeats use whole repeat widths plus a separate remainder.

Assumptions

  • The fullness ratio is selected for the actual fabric and style.
  • Repeat width is ignored in gather mode and applies only after a pleat style is selected.

When a tested commercial pattern gives different cutting dimensions or layout instructions, follow that pattern.

Worked example

  • Default gather: 40 in finished width at 2× fullness
  • Comparison pleat: 40 in finished width at 3× fullness with a 4 in repeat

The default gather needs 80 inches of source width and 40 inches of take-up. Repeat count does not apply to gathers. The 3× pleat comparison needs 120 inches, 80 inches of take-up, and ten complete 4-inch repeats.

Verification note

Pin or baste a short sample because fabric weight changes how a ratio looks in practice.

Learn and verify

Questions from search

How much fabric do gathers need?

Multiply the finished width by the fullness ratio. A 40-inch panel at 2× fullness needs 80 inches of flat fabric before side hems.

How many pleats fit in a finished width?

Divide the finished width by the pleat repeat width. The calculator counts only complete repeats and shows the source width that ratio requires.