The value of a properly fitted suit jacket can't be overstated. Wearing one, a person looks well-dressed, professional and ready for the job. Without one (or in an ill-fitting one), a perfectly competent worker may appear disheveled, unprepared and entirely unprofessional. However, because most suit jackets are manufactured only in standard sizes (and because many people don't fit perfectly into one of these “standard size” categories), finding a perfectly fitted suit jacket can be difficult. Hiring a tailor to fix the fit can also be problematic; tailoring fees can be quite expensive. If you’re relatively proficient in sewing, however, you may be capable of lengthening your suit jacket on your own.
Turn the jacket inside out and inspect the sleeves and hem to see if there's any extra fabric. A good jacket will have a fairly substantial hem, usually with the extra fabric sewn and hidden in the interior lining. If there is no extra fabric, you won't be able to lengthen the jacket.
Carefully take out the stitches of the hem of whatever part of the jacket you're trying to lengthen by using a seam or hem ripper to pull out the stitches. Be careful not to snag any of the fabric as you're pulling.
Remove all of the hem's stitching so that the extra fabric can be pulled out from under the jacket's lining. Once the needed amount of fabric has been pulled out, fold back the extra fabric to create a new hem. Use pins to hold the new length in place, being careful to make sure that the hem is even.
Stitch the new hem into place using a sewing machine.You may also use fusible iron-on web patches to hold up the new hem if you don't have time to sew it; however, sewing is much more permanent. If you're sewing a lengthened skirt on the bottom of a jacket, try to re-create the front corners as accurately as possible. You probably won't be able to completely re-create them, but with careful measuring, you should be able to come close to the shape of the original.
Complete your alteration job by ironing out all of the old creases left from the previous hem. While all the creases may not be completely removed after the initial ironing, over time they should become less noticeable.