Measure the carpet you want to secure. Subtract 2 inches from both the width and length. For a round carpet, measure the diameter and multiple by 3.14. Then subtract 2 inches from the measurement. For example, if the carpet measurement is 18-by-22 inches, cut the padding to 16-by-20 inches. Alternatively, if the carpet has a diameter of 18 inches, cut the padding to a circumference of 54 1/2 inches.
Cut a piece of rug pad to match the measurements in Step 1 using scissors. Rug pad is available at most hardware stores.
Clean the floor where you want the carpet will be placed. Sweep or vacuum to remove debris; mop the floor using your preferred hardwood mop solution to remove debris from the floor's surface. Let the area dry completely.
Place the rug pad where you want the rug to rest. Follow the manufacturer’s instructions for proper placement. Some require the rough sticky side up and others want it down. Still others feature lining you have to remove.
Place the carpet on top of the line. Position it so that it is centered on top of the rug pad.