How To Measure Sink Drain Size | A Complete Guide

When it comes to installing or replacing a sink or any of its the first rule is to measure that specific part before you buy a new one for replacement. The same rule goes for measuring the size of a sink drain. But if you don’t have that time for doing the research, then our how to measure sink drain size guideline will be a great help. 

You will find the correct and easiest way to measure your sink drain size where you only need a measuring tape to measure out the top of your drain hole and later the narrowest part of that hole where the tailpipe connects. This way you will be able to tell the diameter of your sink drain hole. 

So if you are struggling to measure your kitchen sink or bathroom sink drain the correct and easiest way to measure that is fully explained here with supporting details like standard drain size, sink strainer replacement technique, and how you can remove your stuck sink lock nut, and so on. 

A Complete Guide To Know How To Measure Sink Drain Size

The standard size of a sink drain is considered a three-and-a-half-inch sink opening and a one-and-a-half-inch tailpiece. No matter what kind of sink strainer you are using the size will remain the same of the strainer and the sink drain hole. 

Usually, if you measure any kitchen sink hole the top will be 1 and a half inches and the bottom opening will be a little bit less like 1 and ¼ inches or so. But if you want to check that out and make sure the size is correct you can also do that simply by using a measuring tape.

So put the measuring tape on top of the sinkhole opening when the strainer gasket sits and note the size down. Then place the tape onto the shallow part of the drain hole to get the measurement when the tailpipe gets fixed. 

This way you’ll have two size measurements that will tell you the sizing of your sink drain strainer and also the width of your tailpipe at the same time. Usually, when you want to replace a faulty sink drain strainer you need this measurement to purchase a new one that will be the same size. 

How To Measure Bathroom Sink Drain Size?

Usually when it comes to a bathroom sink the size, the style, and the design may vary a lot so you need to be very careful when you want to remove the old sink drain and replace it with a new one. But the drain hole size for any bathroom sink mostly remains the same which is in between 1.25-inch to 1.625-inches. 

So when you are measuring the drain size firstly measure the top part width where the drain stainer lip sits and also measure the inside of your drain hole which will be narrower. For example, if the top part of your sink drain is 1.5-inches then the inside hole might be 1.25-inches or so. Also do not forget to check the manufacturer’s guide where the recommended measurements will be mentioned. 

How To Measure Kitchen Sink Drain Size?

To measure your kitchen sink drain size follow the steps down below:

  1. First,t you have to measure the drain opening of your drain and for that, you need a measuring tape and place it on the widest sides of your drain which will tell you the diameter of your drain circle
  2. Now you need to measure the depth of your drain so push the measuring tape inside from the sides and see how deep it goes. Measure the shallowest point of your drain surface inside
  3. Always make sure you are noting down every measurement. Now the drain strainer will be a little wider on top and narrower on the bottom so it fits down into the drain hole. It will be a good idea if you take your old strainer with you when you are buying a new one so you know which one to pick. 

Are All Kitchen Drains The Same Size?

All the manufacturers of kitchen sinks in the market follow the same standard size for kitchen sink drains which is three and a half inches. Another thing to be noted is that kitchen sink drains are larger than bathroom sink drains as kitchen sink drains get used on bigger scales and have to drain more water wastewater and debris.

What Is A Sink Drain Strainer?

Usually, a sink strainer is a stainless steel and you can see it mounted in the middle of your sink. But on top of that, there is a part or strainer basket which has a mesh on top to stop solid food particles from getting straight into your sink drain and block it. In some sinks, the strainer is a screw with the drain and in some, you can just pull it out and clean it when it gets full. 

Kitchen Sink Strainer Type

  • Fixed post-installation style sink strainer: on the bottom, it has a nut for attaching the pipe and the mounting is also done by also a nut. This strainer requires plumbers putty or silicone 
  • Easy lock sink strainer: you don’t need any special tools for it. Here the pipe connection is pretty much the same. Here you also need a plumber’s putty to seal it. And three nuts to tighten the bottom parts.
  • The cross kitchen sink strainer: here the stainer basket fits in nice and neat and you can just push it down to seal it. That type of strainer is the easiest to install and anyone can do it without any help. 

Kitchen Sink Strainer Replacement

To replace your sink strainer grab your channel locks and remove the lock nut and also the nut which is on the backside of the trap. Use a bucket underneath to catch the water inside. This way can easily swing the tailpipe out of the way. 

If the lock nut does not come off use a hacksaw or a Dewalt cutting wheel and cut it at an angle and a flat screwdriver to split the ring apart. When the lock nut is removed you should be able to lift the basket up and out.

Now clean the area up with a paper towel up and down for the new seal to be applied. Next, remove the brass nut of the new strainer to separate the pieces. Now apply some plumbers putty onto the back of the sink basket. 

Now place the strainer onto the sinkhole and push it down. Next slide on the rubber gasket underneath, the paper gasket, and the lower half of the sink basket. Lastly sild on the lock nut and tighten everything into place. 

4 Easy Steps To Know How To Remove Sink Strainer Lock Nut

If you are replacing a sink strainer lock nut you might be thinking to unscrew that nut somehow. But oftentimes when the strainer is too old it gets rusty and stuck due to hard water build-up. So then, the next tactic is to try to cut that lock nut somehow. That’s why these sink lock nuts can be really difficult to get off. 

Sometimes to take out the nut you need to cut them off. As they are made of cheap pot-metal it won’t be a concern for you to replace them. But sometimes it’s a little tricky to find the replacement part, a lot of hardware stores don’t even buy them so you have to buy the whole unit again. So if you are looking for a solution to remove the sink strainer lock nut follow the steps right down below:

Step 1

Use a Sawzall or an angle grinder or an oscillating tool, or perhaps a Dremel tool with a cutting wheel. If you have one of these tools and thought of using them but are not that confident to do that then there is another solution that might work for you. But these tools will make your job much faster.

Step 2

To remove the glue from the lock nut use penetrating oil for a few hours this way the nut threads will get slippery and you’ll be able to get it off easily. If the threads are full of mineral deposits fill a container with vinegar or lemon juice and a Proffitt container under the drain and let the threads and nuts soak for a few hours.

Step 3

Then scrub the mineral deposits away with a wire brush. If you do manage to break the locking nut-free you can make a wrench to hold the drain body while turning the nut or you’ll need a helper to hold the drain body from above with a pair of pliers.

You can even purchase one of those wrenches also. When you cut the lock nut to fix the sink drain or replace the strainer, you can also glue the old lock nut back again. Then you can get everything cleaned up with a wire wheel. When you are done use some anti-cease to make sure the corrosion does not come back. Then everything will spin together nice and neat again. 

Step 4

When you put everything back together there are things you can do to make sure the nut does not lock up like this. Like, make sure the plumber’s putty does not get into the threads and you have to trim off the plumber’s putty before you assemble it. 

Final Verdict

With all that discussion now you can look for a solution when you have any problem regarding your kitchen or bathroom faucet you can just look into this article about how to measure sink drain size and we have also included other related information about any kind of sinks that you might deal with.

Frequently Asked Questions (FAQ)

What Is A Kitchen Sink Waste Pipe?

For any kind of sink, it is mandatory to measure the plumbing underneath your sink which includes the drainage system, the waste pipe fitting, fixing the water supply, P-trap, and finally the waste line. 

So the area from the tailpipe to the waste line is a part of the sink waste system. The kitchen sink waste pipe takes the nasty gas, small food particles, and wastewater down to the main sewer line and keeps your sink plumbing clear and odorless. 

How Big Is A Standard Sink Pipe?

in modern times the standard size for a sink pipe is one and a half inches and in a few cases one and quarter-inch PVC pipe that connects the sink drain strainer with the garbage disposer.

How Do I Choose A Kitchen Sink Strainer?

As we’ve already mentioned that there are mainly three types of kitchen sink strainers available in the market you can choose according to their material or design or based on their installation techniques. Quality and brand also matter for many people when it comes to buying any kitchen sink parts. 

Are All Kitchen Sink Strainers The Same Size?

As we’ve mentioned earlier that all kitchen sink drain size is the same and so does the strainer. So no matter from which manufacturer you’re buying the strainer they will perfectly fit all the time. But the design of the strainer might be different. 

Are All Kitchen Sink Basket Strainers A Standard Size?

Kitchen sink manufacturers follow the same standard size for their kitchen sink strainer and also for the kitchen sink basket strainer. So no matter which basket strainer you are buying it will fit any standard sink drain opening of 3 and ½” or 4” max. 

How Do I Replace A Sink Basket Strainer?

When you take out a sink basket strainer there are a couple of different styles available in the market. For example, some have a large outside lock nut that holds the strainer fittings together.

  • So to install a sink basket strainer first disassemble all the parts and underneath the top basket strainer flange put a rope of plumber’s putty about half an inch thick push it all the way around
  • Now push the basket strainer onto the drain hole. Some excess putty will squeeze out so scrape that excess
  • Now place the rubber and washer gasket up and screw the lock nut 
  • To tighten use a wrench and tighten the last ring to hold everything in place
  • Lastly, lock the basket strainer plug on top of the strainer

How Do You Measure A Sink Strainer Plug?

To measure the sink strainer plug first hold your measuring tape right across the bottom of the sink. This way you can tell the correct diameter of the plug space. Usually, a plug hole measures 78 millimeters in diameter at the top and that is the standards size for all kinds of plug-ins.