How to Measure for an Undermount Sink With Granite Counters

Measure the width of the hole in the granite countertop with a tape measure by extending the tape from the lip of the hole on the left side of the opening along the rear to the lip of the hole on the right side. Write the measurement down onto a piece of paper. Repeat the process along the front of the opening for accuracy, in case the hole for the sink is oddly shaped.

Use the tape to measure the width of the hole from front to rear using the same methods, measuring first the left side of the opening, and then the right. Mark each measurement down along with the others on the piece of paper.

Open the cabinet door beneath the sink and measure the space between the front of the hole and the inside front of the cabinet frame. Do the same for the rear of the hole and the rear of the cabinet frame as well. Write these measurements down.

Run the tape from the bottom of the counter to the floor of the cabinet interior to determine the depth of the space available within the cabinet and write the measurement down.

Create a rough sketch of the countertop on the piece of paper, with the position and shape of the hole for the sink drawn onto the sketch. Place the measurements you noted onto the sketch, positioning them along the lines of each measured area so that you can note at a glance the space you have to work with when choosing your sink.

Measure the countertop from the front edge to the backsplash. Subtract five inches from the measurement to allow space for a faucet installation. Make a second measurement of the countertop from left edge to right, subtracting four inches from the amount to provide room on each side for the edges of the cabinet when mounting. Use these measurements, as well as the counter depth measurement, for choosing a sink instead if there is no pre-cut hole in the granite surface.