Security Deposit Interest Calculator — Maryland & Connecticut

For tenancies that started on or after January 1, 2015, the rate is 1.5% or the 1-year U.S. Treasury yield on the first business day of the calendar year, whichever is greater. For 2026 that is 3.47%. Interest is simple interest for each full month the landlord holds the deposit.

When the deposit is under $50, or the landlord held it for less than 6 months. No interest is due for a period shorter than a full month, which can happen at the end of a lease.

Each month uses the rate for the calendar year it falls in, so a tenancy from mid-2023 to mid-2025 mixes the 2023, 2024 and 2025 rates. The table under the result shows the split.

Since January 1, 2012, the rate for each calendar year is the deposit index the Banking Commissioner sets under § 36a-26. For 2026 it is 0.49%. The landlord pays the interest on each anniversary of the tenancy, or credits it toward rent, and pays any interest accrued since the last anniversary within twenty-one days after the tenancy ends.

It follows the Department of Banking's interest table: within each calendar year, full months earn the rate ÷ 12 and leftover days the rate ÷ 365, as simple interest. No interest is owed for a month in which rent was more than ten days late, unless the landlord charged a late fee.

It covers Maryland and Connecticut. Other states and cities that require deposit interest set their own rates and rules.