As you upgrade your 11v11 stadium, the income received per match increases. However, as a club grows in size the core fans can get diluted. Despite bringing in more money, a new stadium will slightly decrease the “home advantage” a club has.
Level 1 – 100,000 income per match
Level 2 – 200,000 income per match
Level 3 – 300,000 income per match
Level 4 – 400,000 income per match
Level 5 – 500,000 income per match
5v5 stadiums bring in 50% of the income. The upgrades for 5v5 stadiums are purely cosmetic.