From Brotato Wiki
Upgrades
Upgrades are stat improvements that happen at each level up. Luck affects the rarity of upgrades. However some levels have 100% rarity rates:
- Level 1: 100% Common
- Level 5: 100% Rare
- Level 10: 100% Epic
- Level 15: 100% Epic
- Level 20: 100% Epic
- Level 25: 100% Legendary
- Every 5th level after: 100% Legendary
Please note that in the game files Rare is called "Uncommon" and Epic is called "Rare" but I think those names are bad and I edit the wiki so it's like this