Security Deposit Interest Calculator

Security deposit interestis the earnings that accrue on a tenant's security deposit while the landlord holds the funds. In many US states and jurisdictions, landlords are legally required to pay interest on security deposits held for more than a specified period (typically 6 to 12 months). The interest rate is set by state law and varies significantly - from 1% in Vermont to 5% in Massachusetts. Our Security Deposit Interest Calculator helps both landlords and tenants compute the correct amount of interest owed, ensuring compliance with state-specific regulations and avoiding disputes at move-out.

1. 1. Enter Deposit Details: Input the security deposit amount, the date the tenant paid the deposit (move-in date), and the date the deposit was or will be returned (move-out date). The calculator automatically computes the exact number of days and years the deposit was held.
2. 2. Select Your State/Jurisdiction: Choose from 17 states plus Washington DC with built-in interest rate presets. Each preset includes the statutory interest rate and a reference to the relevant state law. If your state is not listed or uses a custom rate specified in the lease agreement, select "Custom Rate" to enter your own percentage.
3. 3. Choose Compounding Method: Most states require simple interest on security deposits, but some lease agreements may specify compounding. The calculator supports simple, annual, semi-annual, quarterly, and monthly compounding. Review the results including total interest earned, total amount to return, and a month-by-month accrual timeline showing how the interest grows over the holding period.

• Deposit Amount: The original security deposit paid by the tenant at lease signing. Interest is calculated on this base amount for the duration it is held by the landlord.
• Annual Interest Rate: The percentage rate set by state law or specified in the lease agreement. For example, Massachusetts requires 5% simple interest, California uses 2%, and New Jersey mandates 2.5%. Some states like New York and Texas do not require any interest on security deposits.
• Interest Earned: The total interest accrued over the holding period. For simple interest: Deposit × Rate × Years. For compound interest: Deposit × (1 + Rate/Periods)^(Periods×Years) − Deposit. The calculator shows both the total and a month-by-month breakdown.
• Total to Return: The full amount the landlord must return to the tenant - the original deposit plus all accrued interest. This is the amount due at move-out, before any lawful deductions for damages or unpaid rent.
• Effective Rate: The actual annualized return on the deposit over the holding period. For simple interest, this matches the state rate. For compounding with fewer than 12 months, this may differ slightly from the nominal rate.

The Security Deposit Interest Calculator is 100% free with no signup required. All calculations are performed locally in your browser - your deposit amounts, dates, and lease information never leave your device. There are no file size limits or usage caps. Built-in state law references for 17 states plus Washington DC ensure accurate calculations, and custom mode supports any jurisdiction or lease-specific rate. Use it as many times as needed to compute deposit interest, verify return amounts, or prepare for mediation. No data is collected, stored, or transmitted.