How much can a landlord charge for late fees?

​Although the fees for paying your rent late may vary from landlord to landlord, the amount charged must be reasonable. As part of a contract, late fees are not supposed to be punitive. For example, a late fee of $25 assessed after a five-day grace period may be reasonable, while a late fee of $10 per day after the first of the month will likely be deemed excessive if the issue comes up in court. You should be careful about signing a lease that includes such charges.