Compare calculators

Both calculators run independently — change the inputs on either side to compare results.

Seam Allowance Fabric Calculator

Calculate how much extra fabric you need when changing the seam allowance from what a pattern specifies. Essential when adapting European (1 cm) patterns to US (5/8 inch) standards, or vice versa.

Original Fabric Requirement (yards)

Pattern Seam Allowance

Desired Seam Allowance

Number of Seams (seams)

Fill in the required fields to see your result.

Sewing

Fabric Gathering Calculator

Compute the flat cut length of fabric needed to gather down to a target finished length, using a chosen gather ratio. Useful for ruffles, gathered skirts, curtain headers, and shirring projects.

Finished Gathered Length (inches)

Gather Ratio

Fill in the required fields to see your result.

Key differences

	Seam Allowance Fabric Calculator	Fabric Gathering Calculator
Category	Sewing	Sewing
Inputs required	4	2
Result	Adjusted Fabric Needed (yards)	Fabric Length Needed (inches)
What it does	Calculate how much extra fabric you need when changing the seam allowance from what a pattern specifies. Essential when adapting European (1 cm) patterns to US (5/8 inch) standards, or vice versa.	Compute the flat cut length of fabric needed to gather down to a target finished length, using a chosen gather ratio. Useful for ruffles, gathered skirts, curtain headers, and shirring projects.