How This Calculator Works
This calculator shows a late fee two ways: as a share of one month's rent, and as a yearly cost if a charge like it recurred every month. If you enter a grace period, the calculator treats rent paid within that window as carrying no late fee (which is how most leases with a grace period work). Any daily fee applies only to the days past the grace period.
The point is to size the fee, not to judge whether it is legal. Whether a particular fee is allowed depends on your state's law and your lease. Late fee rules vary widely: some states cap the fee, some require it to be reasonable relative to the landlord's actual costs, some require a grace period, and some leave it to the lease. A sourced, state-by-state breakdown is being added to our late fees guide.
Frequently Asked Questions
- How do I calculate a late fee as a percentage of rent?
- Divide the total late charge by your monthly rent. For example, a $75 late fee on $1,500 monthly rent is 5% of one month's rent. Looking at a fee as a share of rent is a quick way to gauge how large it is, separate from whether your state's law allows it.
- Do all states allow late fees?
- Late fee rules vary by state. Some states cap the fee (as a percentage of rent or a flat amount), some require the fee to be reasonable relative to the landlord's actual costs, some require a grace period before a fee can apply, and some leave the question to the lease. Commercial leases are generally freedom of contract. Check your state's rule and your lease.
- What is a grace period?
- A grace period is a set number of days after the rent due date before a late fee can be charged. Whether a grace period is legally required varies by state, but many leases include one. If your lease has a grace period and a fee is charged before it expires, the fee may not be enforceable — confirm how your lease defines the grace period.
- Why do daily or compounding late fees add up so fast?
- Some leases charge a flat late fee plus an additional amount for each day rent stays unpaid. Because the daily portion keeps accruing, the total can grow well beyond the initial flat fee. This calculator lets you enter both a flat fee and a daily fee so you can see the combined charge.