1. Prepare your duct tape. Lay the roll of duct tape on a flat surface with the adhesive side facing up.
2. Measure the amount of tape you need. Measure the length of the piece of duct tape you need using a ruler or measuring tape.
3. Make a mark. Once you have measured the tape, make a mark on the adhesive side of the tape at the desired length.
4. Cut the tape. Use a pair of scissors to cut the tape along the marked line.