Security Deposit Deduction Calculator

Security deposit deductions, explained

Normal wear and tear vs. damage

The line that decides most deposit disputes is the one between normal wear and tear, which a landlord cannot charge for, and damage, which they can. Wear and tear is the gradual deterioration that comes with ordinary living. Damage is harm beyond ordinary use — usually from negligence, accident, or a pet. When it's damage, you still can't charge full price on an aging item; you prorate it by useful life (next section).

The remaining-useful-life rule

An item doesn't last forever, and a tenant shouldn't pay to replace something that was already near the end of its life. The rule is simple: charge only for the useful life the tenant used up early. Take the replacement cost, and multiply by the fraction of useful life that was still remaining at move-out.

Worked example. A carpet costs $1,000 to replace and has a 10-year useful life. At move-out it was 8 years old, so 2 of 10 years — 20% — of its life remained. The tenant is typically chargeable for $1,000 × (2 ÷ 10) = $200, not the full $1,000. If that same carpet were 10 years or older, it would be fully depreciated and typically $0 is chargeable — the calculator shows that line at $0 rather than hiding it, because a $0 line is exactly what protects you from over-deducting.

What is never prorated

Three things are billed in full, not depreciated: cleaning (a unit returned dirtier than it was rented is charged the actual cleaning cost), unpaid rent, and other lease-authorized charges. And removed or missing items — a stolen appliance, a taken fixture — are charged at full replacement cost with no proration, because the landlord is out the whole item, not a fraction of its life.

HUD useful-life reference table

Most states — California included — have no statutory useful-life table. The widely used reference is the HUD Appendix 5D life-expectancy chart, and courts commonly look to industry standards like it. These are typical figures, not law; adjust for grade and condition.

What an itemized statement must contain

A defensible statement lists each item separately: what it was, where it was, the actual repair or replacement cost, and — for prorated items — the age, useful life, and percentage charged. Vague lump sums like “cleaning/repairs — $600” are the single most common reason deductions are thrown out. Most states also require the statement in writing within a set deadline (14–45 days is typical), and some require receipts above a threshold. The calculator's PDF lays this out in the expected format and includes a plain-language method statement explaining how each figure was reached.

Why documentation decides disputes

Proration math is only half the case; the other half is proof the damage existed and cost what you say. Move-in and move-out photos establish the before-and-after, and receipts or invoices establish the cost. Build a timestamped walkthrough with the Condition Report tool, price the work with the Unit Turn Calculator, run the deductions here, then send it with the Deposit Return Letter.

Related tools: Condition Report · Unit Turn Calculator · Deposit Return Letter · Deposit Interest Calculator · Late Rent Notice

Every verified deadline, shortest first

26 states checked against their statute. A state appears here only with a real citation and a verification date — the rest are left out rather than guessed at.

This calculator applies the remaining-useful-life method commonly used to prorate security deposit deductions. Useful-life figures reference the HUD life-expectancy chart, an industry standard rather than statute. Most states do not publish an official useful-life table, and deadlines and requirements vary. This is general information, not legal advice. Confirm your state's rules before sending a deduction statement. See our Privacy Policy and Terms of Use.