Alterations Calculators
Hemming, taking in, letting out, tapering and garment alteration calculations.
Hem Shortening Calculator
Calculate new hem position and fabric to remove when shortening.
Taking In Calculator
Calculate how much to take in at seams for a smaller fit.
Letting Out Calculator
Check seam allowances and calculate letting-out possibilities.
Tapering Calculator
Calculate tapering amounts for gradual seam adjustments.
Shoulder Adjustment Calculator
Calculate shoulder width and slope adjustments.
Crotch Depth Calculator
Calculate crotch depth adjustments for trousers.
Rise Adjustment Calculator
Adjust trouser rise for comfort and fit.
Armscye Calculator
Calculate armscye (armhole) circumference and adjustments.
8 free calculators in Alterations
Garment Alterations Guide
Garment alterations transform an off-the-rack or previously worn garment into a better fit. The most common alterations are hemming (shortening trousers, skirts or dresses), taking in (making garments narrower), and letting out (making them wider using existing seam allowances).
When taking in a garment, the total reduction is divided equally across multiple seams for a balanced result. For example, taking in a skirt by 4cm at the waist means removing 1cm from each of the four seams (two side seams, front and back). When letting out, you are limited by the existing seam allowance — most ready-to-wear garments have only 1–1.5cm seam allowances, limiting how much you can let out.
Trouser alterations require understanding of rise (the distance from waist to crotch) and crotch depth. The crotch point sits about 2.5cm below the body's lowest point for comfort. Shoulder adjustments affect the entire garment silhouette and should be made before other alterations. The armscye (armhole) is the most complex curve to alter and must maintain the correct circumference for sleeve fit.