Fortunately, using the key signature calculation method, one only has to memorize seven.




In the calculation method, each key signature is assigned a numeric value based on the number and type of accidentals. Sharps are positive; flats are negative.




The key of C Major has no accidentals; therefore, its numeric value is 0.




The key of D Major has two sharps; thus, its numeric value is 2.




The key of E Major has four sharps - a numeric value of 4.




The key of F Major has one flat; therefore, its numeric value is -1. (Remember: flats are assigned negative numbers)




The key of G Major has one sharp. Its numeric value is 1.




The key of A Major has three sharps - a numeric value of 3.




Finally, the key of B Major has five sharps - giving it a numeric value of 5.




These seven values must be memorized before we can proceed.




Next, let's compare Cb, C, and C# Major.




If we start at C Major and subtract 7, we end up at Cb Major.




If we start at C Major and add 7, we end up at C# Major.




These two numeric relationships can help us calculate keys that we do not know.




Let's figure out Eb Major. First, start with E Major, which has a numeric value of 4.




To convert to Eb Major, subtract 7.




The result is -3; thus, Eb Major has 3 flats.




Let's try F# Major. Start with F Major, which is -1.




To convert to F# Major, add 7.




The result is 6; thus, F# Major has 6 sharps.




Next, we will examine minor scales. Compare C Major and C Minor.




To convert a major scale into its parallel minor, simply subtract 3.




Let's calculate D Minor. We will start with D Major, which is 2.




Next, simply subtract 3.




The result is -1. Therefore, D Minor has one 1 flat.




Next, let's try F Minor. We will start with F Major, which is -1.




Next, subtract 3.




The result is -4. Thus, F Minor has 4 flats.




Some key signatures require two conversions. For example, let's calculate G# Minor.




Start with G Major, which has a numeric value of 1.




Next, add 7 to get to G# Major.




Finally, subtract 3 to convert to G# Minor.




The result is 5. G# Minor therefore has 5 sharps.




Using the calculation method, it is possible to calculate key signatures which have more than seven accidentals.