sound volume in mp3

Why does the sound level on an mp3 come out so much lower than the wav file. My recording in the wav is about right but to hear the mp3 version I have to really crank up the volume control.

Are you playing both the WAV and the MP3 in the same media player?
What media player is it?

recorded tape onto my computer. Play the wav file - vol is quite high. Play the exported mp3 format and the volume is very low and I have to turn it right up to hear the sound.

How?

How?

Are you sure that it is not just the media player(s) playing them at different volumes?

both played through the computer Windows media player

Try importing both files back into Audacity. Do they look and play the same in Audacity, or is the WAV version still much louder?