Let's say you bought USD/JPY and it goes up by 1% from 120.00 to 121.20. If you trade one standard $100K lot, here is how leverage would affect your return:
Leverage Margin Required % Change in Account
100:1 $1,000 +100%
50:1 $2,000 +50%
33:1 $3,000 +33%
20:1 $5,000 +20%
10:1 $10,000 +10%...