To reach each next level you need 200 more exp than previous.
Formula for exp to next level is - 200*level - 100
http://dragonera.wikia.com/wiki/LevelingExp on each map you can find manually.
I have experience table for some levels, but its far from complete so I didn't upload it.
In general you get around 50 exp per energy for chapter 1 and its increasing for 100 exp per energy at chapter 5.
Midas aka Howrus. GM of Fairy Tails.