It is rare to find trousers that fit exactly right. In many instances trousers are too long and need to be hemmed. Shops often offer alterations, which can add up to £13.00 to the price of the trousers, but it seems a shame to add the cost of an alteration, when it is something that can be easily done at home with very little expertise, tools or equipment.
Plug in an iron. As the iron is heating, look at the fabric care label on your trousers to find the proper temperature for the iron.
Turn the trousers inside out and put them on. If you are hemming trousers for someone else, have the owner of the trousers put them on.
If you are hemming your own trousers, look in a mirror to gauge the correct length and place a straight pin at that point. If you hare helping someone else, place a straight pin at the place that indicates the proper length. Take the trousers off.
Place the trousers on a flat, hard surface such as a table or ironing board. Measure from the bottom to the place where you have placed the pin, and fold the trouser leg at that point. Measure carefully, so that the length is even all around.
Using the hot iron, press the new hemline into place. Pin around the leg of the trousers about 2.5 cm (1 inch) from the edge. Repeat this and the preceding step on the other trouser leg.
Press both trouser legs together with the iron when you are finished pinning, to make sure that they are the same length. If you are satisfied that both legs are even, you can begin sewing.
Cut about 30 cm (12 inches) of thread that matches the colour of your trousers. Tie a knot at one end.
Stitch just under the line of pins, in an even in and out motion, removing the pins as you go.
When you have stitched all the way around to your starting place, stitch over the area and loop the thread into a knot with the needle. Cut off the excess thread. Repeat this on the other leg.
Make sure all the pins are removed when you finish sewing and try the trousers on one last time to be sure that the hem is even.
Press trousers with the iron again.
Wear the shoes that will be worn with the trousers when taking the measurement for the hem. If a belt or suspenders will be worn, put them on when adjusting the length of the hem for a better fit. If the fabric of the trousers might shrink, wash them first according to the fabric care label.
Be sure to consult the fabric care label on the trousers before applying a heated iron to the fabric.