How to Measure For an Undermount Kitchen Sink

Whether you’re revamping your kitchen or installing a new sink in your freshly-built kitchen, undermount kitchen sinks are an excellent choice. They sit flush (flat) with the countertop, neatly situated in a minimalistic style.

If you’re planning on installing an undermount kitchen sink and aren’t sure where to start, keep reading for a quick, helpful guide.

Taking Measurements

Correct measurements are imperative for seamless installation. If you end up cutting a too-large hole in your countertop, you’ll run into a world of issues as your sink will not fill the gap entirely, and you’ll need a new slab of the countertop. On the other hand, if you cut a too-small hole, it’s really not a big deal as you can fix it, but it is inconvenient.

So, to correctly measure and avoid an undesirable final product, this is what you’ll need:

  • Flat, sturdy surface
  • Measuring tape
  • Pen and paper
  • Straightedge ruler

Before you cut a hole in your countertop, measure your sink. Place the sink on a flat, sturdy surface for measuring. Once you have collected your materials, begin taking measurements.

How To Measure For An Undermount Kitchen Sink

Measure The Length

To measure the length, place the end of the measuring tape on one edge of the sink. Ensure that the edge of the tape meets the outside rim of the sink on that side. Stretch the tape across the sink to the other edge. Write down your measurement and note that it represents the length.

Measure The Width

For the width, extend the measuring tape across the sink from the back to the front. Verify that the tape sits on the outermost rim of the back of the sink. Measure forward towards you, again meeting the outer lip of the sink. Write down your measurement.

Measure The Rim/Lip

For the most part, the “lip” of the sink refers to the space between the edge of the sink and the countertop edge. Generally, the lip isn’t more than 1 inch in length. When installing undermount sinks, this measurement is essential.

All four sides should have measurements in the same ballpark. For variations that are less than ⅛ inch, the measurement is insignificant. However, record your measurements just the same.

Measure The Height

Next, you need to figure out how much space the sink will occupy vertically. To measure this, stretch the tape measure from the top of the sink to the underside bottom of the sink. Ensure that your tape measure is straight. Note the measurement.

The height measurement is critical with undermount sinks, especially if you’re planning on constructing a support apparatus beneath the sink.

Measuring For The Hole

Once you have your list of sink dimensions, you can proceed to the next step, which is slicing a hole in the countertop in question. Before you start chopping away at the countertop, you need to do a few calculations.

Add together the sink lip measurements for the left and right sides, then subtract the answer from the length measurement you recorded earlier. The width is the same concept: combine the sink rim measurements from the back and front sides, then subtract the value from your with measurements.

Since undermount sinks don’t have a lip resting on the countertop like drop-in sinks, the interior measurements should be identical to the cutout size.

Measuring An Undermount Sink For Replacement

Measuring An Undermount Sink For Replacement

Over time and with heavy use, kitchen sinks become worn out. If you need to replace your old sink entirely, it is usually easiest to remove it and get your measurements. Sinks with a wide lip may leave a greater available width, so ensure that you correctly measure the sink before purchasing a replacement.

Follow the steps outlined above to measure the sink. Once you have determined the correct measurements, you can purchase the identical model (if it is still sold) or buy a different sink with the same or very similar measurements.

What Size Undermount Sink Do I Need?

If you’re replacing your current sink, you’ll need to find a sink that meets the existing space. When determining what size of undermount sink you need, it’s essential to consider several additional factors that may impact your decision.

First, consider the size of the space you’re working with. Choose a sink that is appropriately sized to meet your needs and space restrictions. For example, a large sink in a tiny kitchen will absorb and impede your limited counter space. Or, a single small sink in a home with a massive kitchen just doesn’t make sense.

Also, consider the depth you’ll need to accommodate the amount and size of dishes. It’s no fun trying to wash a massive serving tray in a shallow basin, so choose a sink depth that is suitable for your needs.

One of the most important factors to consider is the size of your base cabinet. If you are replacing your sink or working with a preexisting cabinet, you need to determine what size of sink is best for the length of the base cabinet.

Are Undermount Sinks Standard Size?

Kitchen sinks come in various sizes, and undermount sinks are no exception. The standard size kitchen sink is typically between 24-inch and 36-inch in length. The most common sizes of kitchen sinks range from 30-inch to 33-inch in length.

What Size Undermount Sink Fits A 36″ Cabinet?

Cabinets that extend 36-inch in length are prevalent. Generally, a 33-inch sink will comfortably fill a 36-inch base cabinet.

What Size Undermount Sink Fits A 33″ Cabinet?

If you have a 33-inch cabinet, a 30-inch sink should fit comfortably within it. If you go much larger with an undermount sink, you may not have enough room to situate the sink beneath the countertop.

Is There A Standard Cabinet Size?

There is a lot of variability in base cabinet sizing since designs have been created to accommodate smaller spaces to boost efficiency. Standard base cabinets are usually are 12, 15, 18, 21, 24, 26.25, 27, 30, 33, 36, 39, and 42-inches wide. There isn’t one specific standard base cabinet size, as there are many different options to suit various spaces.

How Are Undermount Sinks Installed?

How Are Undermount Sinks Installed

Unlike other sink types, like drop-in sinks that support themselves on the countertop, undermount sinks require more work. As the name implies, the sink is attached beneath the countertop.

Proper installation is imperative to avoiding leakage and ensuring adequate support. Nobody wants to have their sink full of dirty dishes and soapy water crashing down through the cabinet below because then you’ll just end up with dirty dishes and an impromptu slip-n-slide underneath your sink.

Undermount sinks are generally fixed to the bottom of the countertop using a two-part epoxy adhesive. It is then sealed with silicone caulking skirting the perimeter. If you aren’t sure how to install an undermount sink, have a professional give you a hand. They can usually complete an undermount sink installation in half an hour or less.

Can I Top Mount An Undermount Sink?

Generally, it’s best to install undermount sinks as they are intended to be installed: fixed beneath the countertop. This is because some sink models may leave a sharp edge exposed with the rim situated above the counter. The raised lip also makes the sink challenging to seal appropriately.

So, if you want to have a top-mounted sink, and you’re buying a new sink, just buy a type of sink that can be top-mounted. It’ll save you the headache of figuring out how to top-mount a sink that is designed as an undermount.