Rent increase calculator
Two numbers decide whether a raise is worth sending: what it adds over a year, and whether it is inside the cap your state applies. This does both, then reminds you what notice the raise buys you.
Pre-filled with a 4% raise on the site's example unit. Set the percentage OR the dollar field, not both.
New monthly rent, 4.00% increase
$1,924.00
- Current rent
- $1,850.00
- Increase
- $74.00
- New rent
- $1,924.00
- Extra per year
- $888.00
- AB 1482 style cap (5% + CPI, max 10%)
- 8.10%
- California's statewide test; your state may have none, or a lower local one.
The cap test, and what it is measured against
California's statewide cap is the clearest published version of the arithmetic, so it is the one this tool models. Under Cal. Civ. Code § 1947.12 (checked 2026-10-18) a covered unit's rent may not rise by more than 5 percent plus the local change in the cost of living, or 10 percent, whichever is lower — and the comparison is against the lowest gross rental rate charged in the preceding 12 months, not the rent on the last cheque.
The trap in the word "lowest"
California leaves accepted discounts, free months and credits out when it finds the lowest rate — but the same subdivision requires the gross monthly rent and each concession to be listed separately in the lease (§ 1947.12(a)(1), checked 2026-10-18). Write a concession as its own line, never as a lower rent.
Most states have no statewide cap at all. Several have city ordinances that are stricter than anything in state law. The number this page prints is arithmetic; whether you may charge it is a question for your own statute.
The notice the raise buys you
A raise is only effective when notice has run. California requires 30 days for a raise of 10% or less and 90 days for a raise of more than 10%, counting every increase in the 12 months before it takes effect (Civ. Code § 827, checked 2026-10-18). Read the lease as well: a lease may require longer notice than the statute, and then the lease wins.
| Situation | Typical notice | Where it comes from |
|---|---|---|
| Periodic tenancy, raise of 10% or less | 30 days | State statute (CA § 827) |
| Periodic tenancy, raise over 10% | 90 days | State statute (CA § 827) |
| Fixed-term lease | at renewal only | The lease itself |
| Rent-controlled unit | local rule | City ordinance |
Serve it the way the lease names, and keep proof. An increase served badly is an increase that did not happen.
Is the raise worth the turnover risk
Run the number through the turnover cost calculator before you send it. A 4% raise on $1,850 adds about $888 a year. One vacancy at three weeks plus a make-ready usually costs more than that. The raise that keeps a good tenant is often the one that stops short of the cap.
- Send it early — a tenant who hears in October plans; one who hears in November shops.
- Say what changed. You do not owe a reason in most states, but a sentence about taxes or insurance lands better than silence.
- Offer a longer term at a smaller number. A 12-month renewal at 3% beats a month-to-month at 5% you have to re-let in spring.
Sources read for this page
- Cal. Civ. Code § 1947.12 (AB 1482 cap)checked 2026-10-18
- Cal. Civ. Code § 827 (notice of a rent increase)checked 2026-10-18
Related in the binder
