Helpful Toolbox

Security Deposit Interest Calculator

Find out how much interest a landlord owes on a security deposit. Enter the deposit, your state or city's required annual rate, and how long it's been held — the simple-interest amount updates live.

📖 How it works & FAQ

Why landlords owe interest on security deposits

In many states and cities — including Massachusetts, New Jersey, Connecticut, Maryland, Ohio, Pennsylvania (after the second year of a lease), and municipalities like Chicago — landlords must keep a tenant's security deposit in an interest-bearing account and pay the earned interest to the tenant, either once a year or when the tenancy ends. The required rate is usually set by statute or pegged to a local bank's passbook savings rate, so it changes from year to year and from place to place. This calculator applies the standard simple-interest formula most jurisdictions use: deposit multiplied by the annual rate, multiplied by the number of years the deposit was held. Every input is editable because the rules vary so widely. Results are estimates only, not professional, financial, tax, or legal advice — always confirm the exact rate and payout rules in your state law or city ordinance.

How to use it

  1. Enter the security deposit amount you paid (or, as a landlord, collected).
  2. Enter the annual interest rate your state or city requires. Recent required rates have ranged from a token 0.01% to more than 2%, so adjust this to your local figure.
  3. Enter how long the deposit has been held, as whole years plus any extra months.
  4. Read the live results: interest owed, the total the landlord should return, the per-year interest amount, and the total time held.

FAQ

Does every state require interest on deposits?
No. Roughly a dozen states plus several large cities require it; many others don't. Some only require interest above a deposit size, after a minimum tenancy, or for larger buildings. Check your local law first.
Is this simple or compound interest?
Simple. Most statutes compute deposit interest as a flat annual percentage of the original deposit, and many require yearly payouts, which prevents compounding. If your jurisdiction compounds, the true amount will be slightly higher than this estimate.
Where do I find my required rate?
Look up your state attorney general's tenant-rights page or your city's housing department. Cities like Chicago publish the official security deposit interest rate each January.
Can a landlord keep the interest?
Where interest is required, generally no — though some laws let landlords retain a small administrative percentage. Interest can, however, be applied against unpaid rent or lawful deductions at move-out.