A Security Deposit Calculator

A security deposit is a multiple of the monthly rent, hold interest in some jurisdictions, and comes back minus whatever the landlord lawfully deducts.

Monthly rentThe rent payable each month under the lease.Months of rent requiredOne month is usual; two is common for furnished property.Annual interest rate(%)Set to zero where the jurisdiction does not require interest to be paid.Months heldHow long the deposit stayed with the landlord.DeductionsItemised charges for damage, cleaning or unpaid rent.

Deposit required

$1,850.00

Interest owed: $55.50
Refund owed: $1,630.50
Deductions as a share of deposit: 14.86%

Values update as you type. This calculator covers the single scenario its formula assumes — see Common Mistakes for what it leaves out.

The formula this calculator uses

deposit = monthly rent x months required

D: Total deposit paid at move-in
R: Monthly rent
M: Number of months of rent required

How to check the result by hand

1
Find the monthly rent and the required months
One month is usual but the lease or local law may require more. The months figure is a multiplier, so two months doubles the deposit.
2
Multiply rent by months
Eighteen hundred and fifty times one month is eighteen hundred and fifty. This is the cash the tenant pays at move-in.
3
Add any required interest
Where the jurisdiction requires it, deposit times rate times months held over twelve. Eighteen hundred and fifty at two percent for eighteen months is about fifty five.
4
Subtract lawful deductions
Only itemised charges beyond ordinary wear and tear. Two hundred and seventy five of cleaning and damage leaves a smaller balance than the full deposit plus interest.
5
Check the deadline and the paperwork
Most jurisdictions set a deadline for returning the balance with an itemised statement. Missing it can cost the landlord far more than the deposit itself.

For worked examples, common mistakes and the limits of this formula, read the full How To Calculate A Security Deposit page.