Whistle Hole Calculator

This page will assist you in calculating where to place holes in a PVC pipe flute, whistle, or recorder. The calculations will be correct for any type of mouthpiece, since they are based on your measurement of what the base note of the instrument is. The calculator on this page assumes that you will make all your holes the same size, and that they are round.

The first thing that you need to do is to figure out the "base frequency" of your whistle, the frequency it will play when all the holes are closed. You should already have installed the mouthpiece on your flute for this step. Play the pipe and figure out what note it plays, using a computer, a pitch pipe, or a tuner. If you want the pipe to play in a specific key, shorten it until it gets to the desired pitch; otherwise, you can just call the bottom note "do" and reference all the others from that. Usually you do want this bottom note to be the "Do" of your scale. I find that, for a simple six-hole whistle, this gives me the most versatile instrument. However, if you'd like to start from some other place in the scale you can select that from the pull-down menu.

Base frequency (Hz):

Now you need to decide how many holes you want. You can play a note an octave higher than your base note by just fingering the base note (all closed) and blowing a bit harder. Therefore, I usually just make 6 holes, playing do - ti in the lower "register" and jumping up to the higher register to get the high "Do."

Number of holes:

In the boxes below, enter the bore diameter, hole diameter, and pipe wall thickness. The bore diameter is the inside diameter of your pipe; the hole diameter is the size of your drill bit. You may want to experiment entering different hole diameters and see what size bit gives holes that aren't too close together to finger.

Bore diameter:

Hole diameter:

Wall thickness:

Bore area: cm2
Hole area: cm2
Hole acoustic length: cm
NoteFrequency (Hz)Hole Distance from End (cm)

The numbers given in the table above under "Hole Distance from End" are how far you should measure, in centimeters, from the open end (not the mouthpiece end) of your whistle, to the center of the hole. The hole can be rotated to any position around the pipe, as long as it is at that distance; you may want to move some holes a bit off center to make them easier to reach.

If you'd like a full explanation of the physics behind this, look at "Physics of Musical Instruments" here.