Metal gutters divert rainwater from your roof to the ground. With no gutters, rain would run off your roof in a sheet, soaking anyone walking under your eave with water. Properly installing the gutters around your home will reduce leaks, increasing the efficiency of your home's gutter system. An important part of gutter installation is cutting lengths of metal gutter. Properly sized gutters ensure that you cover the entire area of the roof and the gutter does not detract from your home's curb appeal.
Pull the tape measure along the length of metal gutter and mark the length you need to cut the gutter with the carpenter's pencil.
Rest the base of the carpenter's square against the top edge of the metal gutter and align the blade of the square with the pencil mark you placed on the gutter in step 1.
Move the carpenter's square around the gutter, aligning the blade with the pencil line you are extending, until the gutter has a pencil cut line around its perimeter.
Cut along the pencil cut line with a pair of aviation snips. If the section of the gutter you are discarding is on your left, use the right-hand tin snips, and vice-versa if the discarded section is on right. If you have difficulty cutting with the tin snips, make another cut 1- to 2-inches away from the cut line with the alternate hand snip. For example, if you are making the main cut with right-hand tin snips, you will make the second cut with left-handed tin snips. Make sure you place the second cut on the piece of gutter you will be discarding.
Continue cutting along the metal gutter with both pair of tin snips until you have cut through the metal gutter. Cutting in this fashion will eliminate the tin snips from bending or distorting the metal gutter.