Hem Allowance Calculator
Reviewed by Hamza Gujjar, Algorithm Architect & Software Developer
Last updated: July 28, 2026Hem Allowance Calculator
Cutting fabric to the exact finished length forgets the hem entirely - this calculator adds the correct allowance based on your hem type.
Formula
Total Cut Length = Desired Finished Length + (Hem Fold Depth x Fold Multiplier)
Fold Multiplier: Single-Fold = 1x | Double-Fold = 2x
Example
30-inch desired finished length, 1-inch fold depth, double-fold hem:
Total Cut Length = 30 + (1 x 2) = 32.00 inches
Single-Fold vs. Double-Fold
A double-fold hem - folding the raw edge under once, then folding again to fully enclose it - needs twice the fabric allowance of a single-fold hem, but produces a cleaner finish with no visible raw edge exposed, making it the standard choice for most garment hems.
When a Single Fold Is the Better Choice
A single fold is sometimes preferred for very bulky or thick fabrics where a double fold would create excessive bulk, or when a serged/overlocked raw edge is being folded under just once rather than fully enclosed.