Use a hair tie or elastic band: Loop it through the buttonhole and attach it to the button. Add a waistband extender: These devices can add extra width to the waistband. Visit a tailor: A professional tailor can add extra fabric or a gusset to expand the waist. Remember that these methods may not work for all jeans or may not provide a significant increase in size. If your jeans are too tight and uncomfortable, consider purchasing a new pair that fits you well.