How Open Should My Mouth Be When I Sing?

Why the three finger rule does not work

Joyous Black woman, dressed in blue, singing in front of blue wall

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Singers everywhere are told to open their mouths! Sometimes, it is just an attempt to get people to sing and other times they want to hear louder singing. The truth is the front of your mouth may be open enough already. A matter of fact, if you are reading this article, there is a good chance the front of your mouth is too wide open during singing.

What Does ‘Open Your Mouth’ Really Mean?

Be aware that some may say open your mouth and mean the front of your mouth. Others may be indicating the back of your mouth. A voice teacher will usually differentiate by saying the back of the throat or mouth versus just the mouth. But, be careful. That is not always the case. Ask for clarification if needed. The front of the mouth is opened by simply saying “ah.” The back of the mouth or throat opens when you imagine smelling a rose, feeling an egg stuck in your throat, or yawning.

Three Finger Rule

I believe I first heard of the three finger rule in Elementary School. You take three of your fingers, hold them tightly together, and then stick them in your mouth vertically. With three fingers in the mouth, the jaw hangs wide open and supposedly that much space is needed in order to sing properly. Though early, less experienced music teachers may suggest the three finger rule as a viable concept, no good private voice teacher will. The truth is your jaw may need to be open. But, three fingers wide? Not literally. That instruction may work for some who naturally close up a bit after taking their fingers out of their mouth, have smaller fingers, or bigger mouths. For those who take the instruction literally, the mouth may be so wide open that it causes jaw pain. Ultimately, the three finger rule usually does not work and is certainly not the literal amount of space needed to sing well.

How Open Is Too Open

If the mouth is so wide open it causes any kind tension, then it is too open. Go to any amateur choir concert and bets are you will see at least one singer with their mouth ridiculously wide open. Notice that same singer looks tense and uncomfortable while they sing. It also is a bit uncomfortable to watch and looking good while you sing is important too. The mouth does need to be open in order for sound to project loudly into a room, but not too open.

Appropriate Width

An effective method of teaching appropriate jaw width is to place an index finger on each side of your head in front of the ear at the hinge of the jaw. Open your mouth until you feel a space or hole in front of the ear. The hole indicates your jaw is unhinged, which is important in singing. Many can close their mouths almost completely and still create a hole at their jaw hinge.

Compare Yourself to Great Singers

Compare yourself to famous classical and Broadway singers. Try watching Thomas Hampson or Cecilia Bartoli, for instance. As you watch successful singers, you may notice their jaws are just as open as they might be when speaking loudly. For many, the level of openness is not much more and not much less. At the same time, a common way to sing quieter is simply to close the mouth so less sound comes out. Be aware of that as you observe singers. In general, is your mouth as wide open as theirs? Look at yourself in a mirror as you sing and evaluate.