How To Measure Drum Heads: A Simple Step-by-Step Guide

How To Measure Drum Heads: A Simple Step-by-Step Guide

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Your drum head is probably the most critical element of your drummer set.  Why?  It plays a role in the sounds produced during a drumming session. No matter how expensive your set might be, it will sound unpleasant with an old or incorrect head.  Likewise, drumming with a cheap set can sound ethereal if you install high-quality heads So, if you've been considering buying a new set but don't have the cash to shell out, you might instead look to upgrading to new drum heads. However, you need to be bang on the money with the size. Different drum sizes mean there's some risk in swapping the heads. Getting the measurement wrong can affect the quality of sound your instrument produces.  To prevent this, you need to be able to measure the span accurately.  Let's discuss a step-by-step method for measuring the heads of different drum sizes.

Before You Start Measuring Drum Heads

Before you start, you need a couple of tools. These tools are the difference between destroying your set in measuring the head size or getting the right measurement and upgrading the head. You'll need the following tools:
  • Drum keys or wrench
  • Tape measure

Step 1 – Loosen and Remove the Drum Head

Firstly, a drum key is a must-have tool for every newbie or experienced drummer. Not only can you use it to loosen your heads, but you can also use the keys to tune your drums if they slacken.  The drum key is usually part of the package when you buy a set at the store. To remove the head, you need to:
  1. Use the key to unscrew the lug screws on the top of your set. These lug screws are all around the top of the drum and help hold the head tight and firm.
  2. Once you have unscrewed the lugs, remove the metal ring that holds the head in place.
  3. Now, you can take out the drum head. 
You must do this before measuring the head size. Leaving it on during the process can mess up your diameter. 

Step 2 – Measure the Shell or Exterior Circumference

Once you've removed the drum head, the next step is to measure the exterior or shell diameter. To do this, all you need do is: 
  1. Take the tape measure and put it across the open shell from one edge to the other to get a reading for the width or diameter of the shell. For example, if the exterior of your bass drum is 28 inches, you'll be looking to buy a 28-inch head. 
  1. Use your tape measure for the internal diameter of the rims. It might be smaller by a few inches due to the external shell's width in some instances. If you go this route, round the figure up to the closest inch, and you are ready to get a new head for your set. 
Any of these methods should give you the exact measurements you need for the new head size. However, you should measure the shell from various points and take the average of these different diameters. 


As drums get older, they go out of shape and become harder to measure. A bass head is also likely to have thick edges and seams that expand. Manufacturers sometimes cover these edges with additional material.  Aging and manufacturer modifications can alter the circumference. One way to overcome this issue is to wrap a string tightly around the shell. Mark the points that overlap on the string.  You can remove the string, straighten it, and measure the distance between the marked points. Divide the diameter by 3.14. This reading should give you the average of the diameter. 

Step 3 – Measure the Depth

Finally, you'll need to figure out the depth of the drum's interior. Use your tape measure to read the height from the top edge to the bottom edge.  Now, you have the complete dimensions of the head.  When writing down the measurements, it is usually common to write the depth before the width. For example, a bass drum size of 10" by 22" is 10" deep and 22" wide. The width can also be the head size.  Note: If you are trying to describe the size to someone, you would call it a 22" bass drum.  In other instances, you'll probably see measurements listed this way: “10, 20, 15 or 20, 15, 10”  This series of numbers means that your choice will need to fit a 10" bass drum, 20" mounted tom, and a 15" floor tom.  There are various ways of displaying your measurements, depending on the type (snare, bass, etc.) and what manufacturer or country made the model in question.  For example, bass heads are different from snare heads. American brands usually feature different drum sizes from Japanese makers. 

Some Tips to Lookout for When Measuring Drum Heads

When measuring the head of your set, please do the following: 
  1. Ensure you measure the head after removing the metal ring and former covering. Leaving these parts on could result in erroneous readings. 
  2. When measuring the shell's span, take care not to damage or scuff the body. Otherwise, you risk degrading your new drum sets in the long run. 

Final Thoughts 

You can use the steps listed above for almost any type of hand drum size. Once you have the right wrench or key, you can start the process. However, do ensure you have the right size of wrench or key. The wrong sized wrench can damage the lug screws. As explained earlier, this tool should come with your set. If it doesn't, you will usually find the lug screw thread size on the body of your drum set.  Follow the steps above to get an accurate reading of the size of your drum heads. From there, you are ready to upgrade to a higher quality sound.