How To Measure A Sink? (7 Step Guide)

Last Updated On March 1, 2024

Updated on March 15, 2022



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How to measure a sink

You need to know the dimensions of your current sink in order to get the correct size for replacement. Getting accurate measurements can mean the difference between a kitchen sink that works properly and one that is a source of frustration, leaks, and multiple trips to the hardware store.

In this PlumbingNav guide, we will cover: 

  • What you need to know about how to measure a sink
  • Supplies you’ll need for measuring a sink to replace it
  • How to measure a sink (5 Step Guide)

What's In This Guide?

      What You Need To Know About How To Measure A Sink

      It can be helpful to understand standard kitchen sink sizes before measuring yours. 

      A double bowl sink in the kitchen, including a corner sink, will usually be either 30” or 33”. This size refers to the length of the sink. You’ll also need to know the sink width to get the correct size of the cutout. 

      This guide will also help you measure smaller sinks, such as a bathroom sink, prep sink, or bar sink. 

      Bathroom sink sizes vary greatly, but for the average pedestal sink or vessel, you can expect it to have a length of 18 or 20 inches, with some getting as long as 24 inches. 

      In this guide, we will be talking about rectangular sinks. Specialty sinks, especially those in unique, asymmetrical designs, require specialized measurements and may limit your options when it comes to your replacement sink. 

      A round sink will also require special measurements. 

      Type of Sink

      Before you get started, you should learn what type of sink you have. 

      The three most common types of sinks include:

      • Overmount sinks – easy to install and inexpensive but has noticeable lip.
      • Undermount sinks – attractive and space-saving but more expensive and more difficult to install.
      • Farmhouse sinks (apron sinks) – large single bowl sink with a protruding apron (front).

      Your replacement sink should have the same measurements as your old sink’s cutout. 

      You may be able to go from an undermount kitchen sink to an overmount sink and vise versa. However, make your intentions clear to the plumbing contractor. 

      Stainless steel sinks and granite composite sinks can be somewhat forgiving if you are off by an inch or two. However, cast iron sinks require precise measurements. 

      did you know how to measure a sink

      Sink Drain Location

      You should also consider the location of the kitchen sink drain. If the drain is in the center, you will want to find a sink with a similar setup. Alternatively, the drain may be on a specific side. 

      If you get a replacement kitchen sink with a different drain location, you will need to pay to update the plumbing. 

      In addition to your sink drain location, you should also consider how many you have. If you have a single basin, you may want to upgrade to a dual-basin with a garbage disposal. However, you will need to upgrade your plumbing to accommodate a second kitchen sink drain

      Counter Space

      Most homeowners need at least a solid 3 – 4 feet of workspace in the kitchen. Adding more counter space can increase the comfort of your kitchen and even how your family fosters relationships while in the kitchen

      If you have plenty of counter space but want a larger sink, you can cut a larger cutout as long as you have enough cabinet space underneath to support it. 

      A farmhouse sink design may provide a larger sink with minimal adjustments to the cutout and staying within the appropriate length. 

      Supplies You’ll Need For Measuring A Sink To Replace It

      Tape Measure 

      You will use your tape measure to make measurements. You should be able to find a tape measure in your basic toolbox. 

      Tape measure manufactures have stringent regulations to ensure the accuracy of each tape measure, but you need to use it correctly to get the best reading. 

      Silicone Sealant

      Silicone sealant will be handy in the case that you notice a kitchen sink leak or want to ensure that your sink has as tight of a seal as possible. 

      How To Measure A Sink (7 Step Guide)

      Step 1: Turn Off Water

      To prevent accidental water damage, turn off the water to your kitchen sink before measuring it. You can do this at the shutoff valve on the sink or the shutoff valve at your main line

      Step 2: Clean Sink and Empty Cabinet 

      Clean any dishes in the sink. Then, clean the sink itself with bleach to eliminate mold. It’s always best to start with a clean slate. 

      You’ll also want to remove everything from the cabinet underneath the sink, especially dangerous chemicals that can create a hazard if they spill. 

      Most of us have chemicals in the home, which is fine as long as we store them properly and handle them with care. Of course, look into natural alternatives where possible, such as natural enzymatic drain cleaners

      Step 3: Measure Sink (Length x Width x Height)

      Now it’s time to measure the sink. 

      You need to measure the length (left to right), the width (front to back), and the height (drain to countertop level). 

      Always measure twice to ensure you have the right numbers. 

      Step 4: Measure Cabinet

      Measure the length of the cabinet underneath your sink. 

      You need the cabinet to be slightly longer than your sink by at least three inches. For example, if you have a 36” cabinet, you don’t want a sink larger than 33”. 

      Step 5: Remove Sink 

      Shut off water to your kitchen, detach pipes, and remove the overmount sink. 

      This will not be necessary when measuring an undermount sink since undermount sinks are the exact same size as the cutout. 

      Step 6: Measure Cutout 

      Now, you need to measure the cutout where you need the new sink to fit. 

      If you plan to install a new drop-in sink, you need the sink to be slightly larger than the cutout in order for it to rest in the cutout properly. 

      Keep in mind some sinks made from thick materials, such as fireclay sinks, may require more room than the cutout allows. 

      Step 7: Replace Sink

      Finally, you can replace the old sink with the new sink you’ve chosen

      Many homeowners can perform the task themselves with the proper instruction. However, be careful that you don’t unknowingly void your warranty or fall short of local regulations. 

      When you replace the sink, you should also consider upgrading the faucet to an efficient kitchen faucet that can reduce water waste, lower your water bill, and follow efficient water practices.

      FAQs For How To Measure A Sink

      How do you measure to replace a sink?

      Measure the length, width, and depth of the sink. 

      Then, measure the length of the cabinet. 

      How are top mount sinks measured?

      For a top mount sink, you need to measure the cutout as well as the sink to ensure that your sink matches your current look while also fitting in the cutout. 

      What is the standard kitchen sink size?

      Most kitchen sinks are 30” or 33”. 

      How do you measure for an under counter sink?

      Under-counter sinks do not require the additional step of measuring the cutout since they match the size of the cutout perfectly.

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      About Plumbing Navigator

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      We write about “all things plumbing,” helping you navigate common questions, repairs, and the best plumbing products on the market.

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