Renting
Deposit interest
Simple interest on the held deposit, where the jurisdiction requires it to be paid.
The Formula
interest = D x rate x months / 12
Simple interest on the held deposit, where the jurisdiction requires it to be paid.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| I | Interest | currency | Amount owed to the tenant on the held deposit. |
| D | Deposit | currency | Principal amount held. |
| r | Annual rate | ratio | Interest rate as a decimal fraction. |
| t | Months held | count | Time the deposit was held, in months. |
What Each Symbol Means
Icurrency
Interest
Amount owed to the tenant on the held deposit.
Dcurrency
Deposit
Principal amount held.
rratio
Annual rate
Interest rate as a decimal fraction.
tcount
Months held
Time the deposit was held, in months.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate a security deposit page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate A Security Deposit, filed under Everyday Life. Every number the guide produces comes from substituting into this one line.