Security Deposit Interest Calculator

Quick answer

Enter your state, deposit amount and tenancy dates below — the calculator applies your state's own statutory rule: the fixed rate (like the 5% states), the benchmark-linked formula (like the passbook-rate states), or an honest "no statewide interest" result where no statute mandates it. State statute (official text) · 2026-10-28

How the calculator works

For each state the calculator reads three things from that state's statute:

1. Whether interest is required at all. In the minority of states that mandate it, the statute either fixes a percentage or pegs it to a moving benchmark (a passbook savings rate, the federal discount rate). In states with no statewide requirement — and in "local rules only" states — the calculator tells you that instead of inventing a number.
2. How interest accrues. Most interest states require simple interest, credited annually. A few compound. The result panel lists exactly which assumption was applied.
3. The day count. Interest is prorated by actual days of tenancy over a 365-day year, from your start date to your end date (or today if the tenancy is ongoing).

Worked example

A $1,800 deposit held for exactly one year in a 5% simple-interest state earns $1,800 × 5% = $90. Held for 18 months, it earns $1,800 × 5% × 1.5 = $135. The same deposit in a benchmark-linked state earns whatever the current announced benchmark is — which is why those states' guides on this site link the official announcement.

What the calculator cannot do

It does not model local ordinances stricter than state law (though every state guide links them), lease terms more generous than the statute, deductions a landlord may claim against the deposit, or partial-month edge cases in states with month-based rules. Outputs are estimates — see the disclaimer.

Tips before you calculate

• Use the deposit amount, not the rent. The calculation applies to the security deposit your landlord holds — typically one to two months' rent.
• Count full tenancy time. Some states only owe interest after a minimum tenancy (six months in Ohio, one year in New Hampshire, the third lease year in Pennsylvania); the state pages spell out each trigger.
• Check whether your state credits annually or at move-out. Where the statute says interest is credited against rent each year, the move-out figure may be just the final year's accrual — the timing rules are on each state page.

FAQ

Is this calculator free?

Yes, with no signup. The calculations run in your browser — nothing you type is sent to or stored on our servers.

Which states require deposit interest?

A minority do, each with its own rate and conditions — the 50-state guide lists every state with its current rate, eligibility rule and statute citation.

My landlord never paid any interest. What now?

Start with the math on this page and the statute on your state's page, then raise it with the landlord in writing. If that goes nowhere, your state attorney general's consumer protection office (linked on every state page) handles deposit complaints in most states. For a dispute worth real money, talk to a lawyer or legal aid — this site can quantify the claim but cannot advise your case.

Is the result legal advice?

No. It is an estimate of what the statute prescribes, not advice about your lease or dispute — see the disclaimer.