How to Measure the Diameter of a Garden Hose (Inside vs Outside)


How To Measure the Diameter of a Garden Hose

Bringing a lawn and garden to life requires perfectly fitted garden hoses. Using the right sizes around the yard can make a big difference in efficiency compared to using whatever is closest or on hand.

Measuring the diameter of a garden hose correctly is one of the first tasks in selecting the right hose or hose attachment for the job. However, even the most experienced lawn-owners sometimes find that measuring the diameter of a garden hose and it’s related fittings can be a daunting task.

But, it doesn’t have to be, we can make it easy.

First, here’s why you’ll want to know these measurements. Then we’ll go over the the step-by-step process of measuring the diameter by yourself.

If you want to skip the why and just see the tutorial then click this link.

Why Do I Need to Measure the Diameter of a Garden Hose?

Garden hoses don’t last a lifetime and you’ll have to buy a new one eventually. There’s nothing worse than coming home with a brand new garden hose that is completely different from the size, ply, length, or fitting as the one you’ve been using for years.

The more you know, especially the diameter measurement, the more consistent your tool repurchase and gardening technique.

Diameter Affects Water Pressure Measured by PSI
The diameter of a garden hose greatly impacts the water pressure being released from the hose. The flow rate of a garden hose is measured in pounds per square inch (psi) and determines how quickly water pumps through the garden hose.

The size of the garden hose diameter will determine the stream of the psi. Depending on the water source, you may need a water pressure regulator that protects your plumbing. Knowing the diameter of the garden hose may be required to select the appropriate regulator.

Here is an example of a pressure regulator that you can attach to your garden hose system on Amazon.

You can also see this post on our site where we’ve discussed a few different solutions to low outdoor water pressure.

Most importantly, the internal diameter of a hose is often how it’s identified.

This measurement says a lot about what purpose the host serves and at what scale.

For example, a ¾ inch hose is generally reserved for professional use. Don’t be surprised if a salesman asks you to double check that measurement if you walk into the home and garden section of a store asking for a ¾ inch diameter hose.

GHT vs NHT vs BSP: They Are All Different
The functionality of your most prized garden tool requires an in-depth awareness of all its working parts including some of the following expert tips:

  • The Thread Size of a Standard Garden Hose.
  • If you live in the USA or Canada, you probably are familiar with the term Garden Hose Thread (GHT) which is the standard thread for garden hoses. The official title though is National Hose Thread (NHT).

Couplers which have thin walls on the hoses which are made from thin-walled materials have two different designs.

The terms National Hose (NH) describes threads that are made from thick materials. These thick materials are usually used to form valves and other fittings.

Notice that valves and fittings are usually made by cutting and rolling thread pitch (11.5 threads per inch).

All the designations of the fitting have the same size. However, they can be specified according to the internal dimensions of the hose or the pipe.

The standard fittings are either 3/4-11.5NH or 5/8-11.5NH.

Notice that ¾” and 5/8″ are the internal diameters of the hose of the pipe while 11.5 is the thread pitch.

  • One of the most common myths is that Garden Hose Thread (GHT) can be compatible with National Pipe Tapered (NPT); well, they are NOT.
  • If you live anywhere else outside the USA and Canada, the British Standard Pipe Thread standard (BSP) is what is used to determine thread size.

All the domestic fittings formed according to the British Standard Pipe Thread standard has ¾ inch BSP. The thread pitch is 14 threads per inch.

Taps and fittings used for other non-domestic purposes such as farms, factories are different. These taps and fittings use a one-inch British Standard Pipe Thread standard.

What Are Normal Garden Hose Fitting Sizes?

There are four different inner diameters of garden hoses:

  • 3/8″ 10mm,
  • 1/2″ 12.5mm,
  • 5/8″ 15mm or
  • 3/4″ 19mm.

Usually ¾-inch hoses are used for professional purposes and wouldn’t be considered to be a normal residential hose.

How Many GPM Do Garden Hoses Put Out Based on Hose Diameter?

GPM or Gallons per Minute can be detected when you know more about the flow rate of your garden hose.

Here are the four main factors determining your garden hose flow rate.

1. The Hose Diameter

Standard golden hoses are available in 3 sizes; 1/2, 5/8, and 3/4 inch. These sizes determine the internal diameter of the hose. You should choose the size according to the number of gallons you want. Smaller diameter means fewer gallons per minute.

2. Water Pressure

The water pressure is another important factor in determining the flow rate of your garden hose. Water pressure determines the speed of the water through the hose.

Knowing the water pressure is essential for getting the best hose for your garden.

3. Hose Length

There are 4 lengths of garden hoses; 25-, 50-, 75- and 100-foot. The longer your garden hose is, the lower the flow rate will be.

4. Flow Rate Estimation

Due to the presence of many factors; it is difficult to estimate the flow rate.

Using a garden hose without determining the flow rate means you will supply your garden with water without knowing the exact amount of time to stop.

The best and simplest way to determine the flow rate is by using a gallon bucket and watch the time. For example, if it takes 10 minutes to fill a 20-gallon bucket, it means that the flow rate is 2 gallons per minute.

Are Garden Hose Fittings NPT or Compatible to FIP?

Garden hoses are not compatible with NPT. Female International Pipe (FIP) can be compatible with your garden hose.

Notice that there are many abbreviations used. You need to make sure that your garden hose is compatible with all the accessories you are going to use before purchasing anything.

A Quick Comparison of 5/8″ & 3/4″ Garden Hose Sizes

There are many differences between these two types of garden hoses. Here are five of the main differences.

1. Water Volume

5/8-inch hoses are smaller in diameter than 3/4 –inch hoses; that is why they provide your garden with narrower water stream than the 3/4-inch ones.

The diameter and the length of the hose determine the final amount of water coming out of it.

Use 5/8-inch hose carefully to avoid puddling and flooding. If you want a hose providing more water volume, choose the 3/4-inch hose.

2. Application

Most people choose 5/8-inch diameter hoses for their gardens and all accessories fit into them. 3/4-inch hoses are usually used for professional purposes such as public gardens and parks.

Workers need large water volume to save time and cover larger areas; that is why they use 3/4-inch hoses.

Our gardens don’t need this whole amount of water; that is why 5/8-inch hoses are the best unless you have a really wide garden.

3. Lengths

The two types of hoses are available in different lengths from 35 to 100 feet long. Choose the best for your garden according to its width and notice that the longer the hose is, the lower the water volume will be.

4. Cost

3/4-inch hoses are more expensive than 5/8-inch hoses.

5. Weight

Notice that 3/4-inch hoses are heavier than 5/8-inch hoses. The extra construction material of 3/4-inch hoses makes them heavier and more difficult to use in small gardens.

For Reference: 3/4-Inch Hoses VS 5/8-Inch Hoses

Features 3/4-inch hoses 5/8-inch hoses
Water Volume More Less
Applications Domestic Gardens Professional Uses
Cost Less Expensive More Expensive
Weight Heavier Lighter

Step By Step: How to Measure the Diameter of a Garden Hose:

There are many ways to measure the diameter of your garden hose. However, most of them are really complicated. That is why we did the thinking for you and came up with the simplest ways to measure your garden hose diameter.

1. Check the Hose or Ask the Buyer:

The first and simplest way to find out the diameter of your garden hose is to check the hose itself. Many hoses have the exact diameter printed on them to avoid customers this fuss.

The buyers also who have enough experience in dealing with garden hoses know the diameter well. Just ask the buyer and he/she might have the answer if the diameter is not printed.

If the diameter is not printed, don’t worry. We have other simple methods to measure it.

2. Putting Something Inside the Hose (The Dowel Way):

Inserting something inside your garden hose is another simple way to measure its diameter.

Hoses usually have specific sizes such as 1/2 inch, 3/4 inch and 5/8 inch. However, inserting something inside will tell you the exact size.

Notice that you have to remove any accessories before trying this method. Also, avoid inserting any sharp objects in order not to cause any damages or get the hose punctured.

Inserting a dowel is really easy and will tell you the exact size of your hose according to the dowel that fits the hose.

3. Using an Index Card:

If you like experimenting, you may like this method the most. It is the most complicated one but its results are precise.

It is better to try the first two methods first and if they didn’t work properly, go for the Index Card Method.

Here are the steps of this method.

  1. Remove any kind of accessories or nozzles from the hose.
  2. Take an index card and roll it into a tube then insert the tube into the opening at the end of your hose. Make sure at least half of the tube is inside the hose before starting on step 3.
  3. The tube must be allowed to open all the way on the inside the hose.
  4. Next tape the tube so that it holds it’s cylindrical shape when you remove it from the hose.
  5. Carefully remove the paper tube from the hose without letting it unravel.
  6. Finally measure the diameter of the inserted side of the paper tube with a ruler or tape measure. This should be the exact inside diameter of your garden hose.

Standard sizes include 1/2-inch, 5/8-inch, 3/4-inch, and 1-inch hoses.

I hope we have answered all the questions you have. It is important to know how to measure the diameter of your garden hose for the best gardening experience.

Here are a few related articles you may find interesting:

So, Why Don’t You Just Measure The End of a Hose With a Tape Measure?

This was the first question that came to my mind when I started researching this topic.

However, it turns out that there’s actually a good reason behind that! The ends of a hose are not always the same diameter as the rest of the hose! They are usually  a tad bit wider.

So, you just can’t take the diameter of the ends and assume it to be the same as the rest of it. So, while this method would have been the simplest, it really isn’t a good option.

Quoting Hunker,

The male and female ends of the hose are often slightly larger than its inside diameter, so measuring isn’t as simple as holding up a ruler at one end of the hose.

Finally, I hope you’ll find something else helpful on our site. Here are a few more popular articles related to hoses.