The trumpet is a transposing instrument, in Bb. Quite often music is also written for trumpet in C, D, Eb and F. With practise it is possible to transpose into all of these keys.
C Transposition
This is the most common transposition and probably the easiest.
Trumpet in C to Trumpet in Bb = up a tone.
Adding two sharps to the key signature will give you the new one. (for example C major will become D major, F major will become G major).
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| Trumpet in C |
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| Trumpet in Bb |
Eb Transposition
Trumpet in Eb to Trumpet in Bb = up a perfect 4th
To work out the key signature at one flat (G major-C major etc.)
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| Trumpet in Eb |
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| Trumpet in Bb |
F Transposition
Trumpet in F to Trumpet in Bb = up a perfect 5th.
To get the key signature add one sharp.
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| Trumpet in F |
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| Trumpet in Bb |
D Transposition
Trumpet in D to Trumpet in Bb = up a major third
To get the key signature add four sharps.
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| Trumpet in D |
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| Trumpet in Bb |
I would recommend using a sight reading book to practise transposition to different keys. As you get better, move onto exercises that are the next level/grade up.