How Tall Should a Compost Bin Be?

How Tall Should a Compost Bin Be

Alright, we must be at that point in your life where you have decided that it is time to start composting. Maybe it is for your garden you recently planted, or maybe it’s simply to cut down on the amount of trash you are throwing away! Either way, we’ve got you covered on a few specifics of what your compost bin should be.

The first thing you need to consider when building a compost bin is how much you will be composting. An easy way to do this is to create a mock compost bin (a bucket works great for this) and add compost to it for a week. From there, you get an idea of how much you will go through in a month.

On the flip side of things, you will also have to take into consideration how much compost you are hoping to have. If you want to use compost in your garden, you may have to consider the size of your garden.

Now, take the size you think you will need and double it. Your compost bin should have 2 times the volume of finished compost that you want. So, say you wanted 50 cubic feet of compost, you should build a bin that will hold 100 cubic feet.

Another thing to consider is whether or not you want to have multiple compost bins or just one. Many gardeners have multiple compost boxes that are in various stages of composting. This lets them have a compost pile that is new compost and one that is finished compost.

Let’s Talk Dimensions

Running with the idea that you are using this compost bin for your garden, there are 2 things you need to first consider:

  • Depth of compost that is desired per square foot in the garden
  • Size of your garden (length and width)

Note: Use the same units of measurement for all of the measurements! Otherwise, you will be completely overwhelmed with weird numbers…

To get the volume of compost, let’s hope you remember that math they taught you back in middle school… The volume of compost can be determined if you multiply the depth of compost desired per square foot and the size of your garden. Now, take this number and double it to know exactly how much space you need.

A Quick Math Example

In case that middle school math is not quite coming back the way you had hoped, I have a few examples to help walk you through it!

Okay, let’s pretend that your garden is a perfect rectangle that is 20 feet long by 30 feet wide. Let’s also pretend that you have decided that you want to have a 2-inch layer of compost throughout your entire garden. Keep in mind that 2 inches is 1/6th of a foot.

Using the equation we talked about, it would look like this:

Compost bin volume = 2 x length of garden x width of garden x depth of compost.

Now, let’s plug in the numbers from our pretend garden:

Compost bin volume = 2 x 20 x 30 x ⅙

Compost bin volume = 200 cubic feet


If your garden is not in a perfect rectangle (which, let’s face it, most of ours aren’t), that’s okay! You can still determine the dimensions of your garden by measuring the length and width to the best of your ability.

Now, if the garden is more circular than any other shape, we still have an easy way for you to find the area! Determine the radius of the circular garden, and the equation will be pi x radius squared. To see what that looks like in a user-friendly way, here you go:

Area of a circle = 𝝅 x radius ²

More Math (Unfortunately)

Now that you have the cubic feet needed, you have to figure out the dimensions of your bin. There are many charts online that can help you with this! Instead of making you go do more research, I’ll give you a few examples of what dimensions you could look at:

  • 10 feet long x 10 feet wide x 2 feet tall
  • 7 feet long x 7 feet wide x 4 feet tall

Basically, you just have to make sure that if you multiply the length, width, and height together, you get the cubic feet you determined in the last equation!

A Few Other Things To Consider

Since we are hitting on the basic dimensions of building a compost bin, I figure we should probably touch base on a few other things that go along with building a compost bin! First, we need to find a place that is away from any water sources, on level ground, and isn’t in the way of your hustling and bustling. You also need to make sure that you have plenty of brown matter to throw into your compost bin, like grass clippings, manure, leaves, or twigs.

When it comes to building the bin, they recommend using organic materials such as wood that has not been pressure treated. Some folks prefer to use metal or plastic for their compost bins, but it is ultimately up to you and what aesthetic you are going for!

What Is The Minimum Size For A Compost Bin?

Now that we have you properly confused and stressed out, let’s talk about the minimum size for a compost bin. They say that your compost bin must be 1 cubic yard. For those who are using feet instead of yards, that’s a compost bin 3 feet long by 3 feet wide x 3 feet tall.

The reason why you need at least this much space is that as the organic matter decomposes, it will lose about half of its volume. Now, that may seem counterintuitive since the volume will decrease as it composts. However, it is to accommodate for the extra space that the organic waste will take up before it actually breaks down to the volume of compost you need.

I should tell you a little tidbit – if your compost bin is larger, it is actually better… Larger amounts of compost in one area decompose faster than smaller piles.

What Size Composter Should I Get?

Great question! Even though we have hit on how to figure out how big of a compost bin should be, let’s still touch on this one a bit. The first thing you need to consider if you are going to be using a composter versus a compost bin is what type you want to go with.

Once you have researched which type of composter would work best for your family, consider the size of your family. For example, if your family is anywhere from 1-4 people, they suggest a 4.5 cubic feet composter at a minimum. Granted, the larger the family, the larger the composter.

Another thing to consider is if you are going to be only putting food and other compostable household items in the composter or if you will be adding other stuff as well—other stuff meaning garden waste or lawn trimmings such as twigs or grass clippings. If you are adding other things, you are going to want a composter that has a capacity of 15 to 20 cubic feet.