The B♭ trumpet
It's the most common trumpet in concert bands, big bands and popular music. It sounds a whole step (major second) below what's written: for a concert C, the player reads a D. A piece in C major is written in D major, and one in F major in G major.
What about the C trumpet?
Many orchestras use the C trumpet, which doesn't transpose. If your trumpeter plays in C, give them the part at concert pitch.
Flugelhorn and cornet
The B♭ flugelhorn and cornet read exactly like the B♭ trumpet.
Frequently asked questions
Does the key signature change?
Yes, it goes up a whole step: two fewer flats or two more sharps. The tool works it out for you.
Can I turn a flute or violin part into a trumpet part?
Yes, but check the range: what's comfortable on flute can be very high for trumpet.