The rent calculator and lease tracker for landlords.
Prorated rent, late fees, deposit interest, rent increases, affordability, and utility splits — each with the state law behind the number, for all 50 states plus DC. Formerly Prorate Calculator Pro.
Prorated rent calculator
Free, right here. Enter the rent and the move date; the three methods landlords use are worked out below.
Six questions every rental raises
Each calculator answers one of them and shows the statute it used.
How much rent is due for a partial month?
Prorated rent is monthly rent divided by the days in that month, times the days occupied. Some leases and states use a 30-day Banker's Month or an annual rate instead. The app shows all three and flags your state's preferred method.
What late fee can I legally charge?
States set grace periods and caps, or require the fee to reflect actual damages. Flat or percentage fees are checked against your state's rule so the amount on the notice is the amount the law allows.
How much interest do I owe on a deposit, and when is it due back?
State and city rates, including San Francisco, Los Angeles, and Chicago, plus the security deposit return deadline counted from move-out.
How much can I raise the rent?
Rent-cap states use a formula, like California's lesser of 5% + CPI or 10%. The app pulls live CPI, applies the cap, and flags the notice period before you send the rent increase letter.
How much rent can a tenant afford?
The 3x monthly, 40x annual, and HUD 30% rent-to-income rules, evaluated together, from income to rent or rent to income. Tenant screening in one tap.
How do I split a utility bill between units or roommates?
Equal, by square footage, by occupants, or RUBS, with a per-unit breakdown you can send.
A lease tracker that keeps you compliant
Properties, tenants, and leases in one place, with the deadlines that matter surfaced before they arrive.
Lease Tracker
Lease status, days remaining, deposits, and move-in/move-out photos. Open any calculator from a lease and the numbers are pre-filled.
Deadline Alerts
Lease expiration at 90, 60, and 30 days. Rent due reminders. Deposit return deadlines. Rent increase notice windows.
State Law, Cited
Every calculation shows the statute behind it, such as Cal. Civ. Code § 1950.5. General guidance, not legal advice.
Widgets
The next lease expiration, rent due date, or compliance deadline on your Home Screen and Lock Screen.
iCloud Sync
Properties, leases, and saved calculations sync across iPhone and iPad.
On-Device AI Insights
Upcoming lease events ranked by urgency with plain-language next steps. Nothing leaves your phone. iOS 26+.
Free to try. Premium when it earns it.
Your first 3 calculations are free on any calculator, with full state citations.
Free
$0
- 3 calculations, any of the 6 calculators
- State-law citations
- Unlimited calculations
- Lease tracker & alerts
- iCloud sync & widgets
- AI insights
Premium
$39.99 /yr
- Unlimited calculations
- Lease tracker & deadline alerts
- Home & Lock Screen widgets
- iCloud sync
- AI insights (iOS 26+)
- 7-day free trial
Lifetime Premium
One payment, forever yours. All Premium features, no subscription, no renewals ever. Early supporters of Prorate Calculator Pro keep their loyalty price in the app.
Start with three free calculations.