California Rent Increase Calculator: AB 1482 Cap, CPI, Exemptions

A California rent increase calculator comes down to one formula: the most your landlord can raise your rent in a 12-month period is the lower of 10%, or 5% plus the percentage change in the Consumer Price Index for your region, multiplied by your base rent. That cap comes from the Tenant Protection Act, codified at California Civil Code § 1947.12, and it runs through January 1, 2030.¹ Two numbers do the work: your base rent and your regional CPI change. Everything else is about making sure you’re using the right version of each.

Run the Calculation

Take 5% and add your region’s CPI change. Compare the result to 10%. Use whichever is lower. Multiply that percentage by your base rent, and the product is the maximum dollar amount your rent can go up over a 12-month period.¹

Moderate Inflation Example

Say your base rent is $2,000 and your region’s CPI change is 3.0%. The formula gives 5% + 3.0% = 8.0%. That’s below the 10% ceiling, so 8.0% is your cap. $2,000 × 0.08 = $160. Your new rent cannot exceed $2,160.

High Inflation Example

Now say the regional CPI change is 6.5%. The formula gives 11.5%. That exceeds 10%, so the hard ceiling of 10% applies instead. On a $2,000 base rent, the maximum increase is $200, bringing the new rent to $2,200. The 10% ceiling exists to prevent runaway increases when inflation spikes.²

Find Your Regional CPI

The U.S. Bureau of Labor Statistics publishes CPI for All Urban Consumers (CPI-U) data for several California metropolitan areas, including Los Angeles, San Francisco, San Diego, and Riverside.³ Which month to pull depends on when the increase takes effect:

Increases effective before August 1: use the change between the April CPI from the prior calendar year and the April CPI from the year before that.
Increases effective on or after August 1: use the change between the April CPI from the current calendar year and the April CPI from the prior year.

If April data isn’t published for your specific region, use March figures. Round the resulting percentage to the nearest tenth of a percent.⁴ For the Los Angeles area, the maximum allowable increase for the period starting August 2025 was 8.0%, reflecting a 3.0% CPI change on top of the 5% base.⁵

Find Your Base Rent

Base rent is not necessarily what you’re paying today. The statute defines it as the lowest gross rental rate charged for the unit at any time during the 12 months before the effective date of the increase. If the landlord offered a lower rate at any point during that window, that lower number is the base.¹

Temporary concessions are treated differently. Discounts, incentives, or credits that the landlord offered and the tenant accepted are excluded from the base calculation. If your lease shows a $2,200 gross rent with a $200 monthly concession bringing your effective payment to $2,000, the base rent for the cap is $2,200. The statute requires gross rent and any concessions to be listed separately in the lease or amendments precisely so this stays visible.⁴

The Two-Increment Rule

Even when the total stays under the cap, a landlord cannot divide an increase into more than two separate steps within any 12-month period. A 3% increase in March followed by a 4% increase in July uses both allowed increments for that year. A third increase, no matter how small, would violate the law regardless of whether the combined total remains under the overall cap.¹

Does the Cap Even Apply to Your Unit?

The formula is only useful if your rental is covered. Section 1947.12 reaches most residential rentals: apartments, duplexes, and other multi-family housing where the owner does not live on-site, plus single-family homes and condominiums owned by a corporation, a real estate investment trust, or an LLC with at least one corporate member.¹ Several categories are exempt:

Units that received a certificate of occupancy within the last 15 years, calculated on a rolling basis. Mobilehomes are excluded from this exemption.
Individually owned single-family homes and condos, but only if the owner is not a corporation, REIT, or LLC with a corporate member, and only if the landlord has delivered a specific written exemption notice to the tenant.
Deed-restricted affordable housing for very low, low, or moderate-income households.
School dormitories owned and operated by a college, university, or K–12 school.
Properties where a local rent stabilization ordinance caps annual increases at a lower rate than the state formula.

That last category is where the calculator alone can mislead you. Over 30 California cities, along with unincorporated Los Angeles County, run their own rent stabilization programs. Los Angeles, San Francisco, Oakland, Berkeley, Santa Monica, San Jose, and Beverly Hills all have independent rent control, and some tie allowable increases to a fraction of the CPI, producing caps as low as 3% to 5% in a given year. If a local ordinance restricts increases to less than the state formula, the local ordinance controls, and the state cap drops out.⁴ Check with your city’s rent board before relying on the state number.

The Single-Family Home Exemption Notice

An individually owned single-family home or condo is not automatically exempt. The landlord must deliver written notice to the tenant using language the statute prescribes, stating that the property is not subject to Section 1947.12 or to the just cause eviction rules in Section 1946.2 and that the owner is not a REIT, corporation, or LLC with a corporate member. For any tenancy that started or renewed on or after July 1, 2020, that notice must appear in the rental agreement itself. Without it, the cap applies regardless of ownership type.¹

Vacancies: The Cap Doesn’t Limit a New Tenant’s Starting Rent

When a tenant moves out and no one from the prior tenancy remains, the landlord can set the initial rent at any amount for the new tenant. The cap in § 1947.12 does not apply to that first number. It governs later increases once the new tenancy begins.¹ The protection runs with the tenancy, not with the unit.

Notice Requirements

A correctly calculated increase can still be invalid if the landlord botches the notice. Civil Code § 827 sets the rules. The notice must be in writing. It can be hand-delivered to the tenant or served by mail following Code of Civil Procedure § 1013.⁶

How many days the landlord must give you depends on the size of the increase, measured against the lowest rent charged in the prior 12 months (including any other increases during that period):

10% or less: at least 30 days before the increase takes effect.
More than 10%: at least 90 days before the increase takes effect.⁶

When the notice is mailed and both the mailing address and the tenant’s address are within California, five calendar days are added to the notice period. A 30-day notice served by mail becomes 35 days. A 90-day notice becomes 95.⁷ Missing by a single day can invalidate the increase.

If Your Landlord Charges More Than the Cap Allows

Civil Code § 1947.12(k) lets tenants sue for the amount of any overpayment, injunctive relief, and, at the court’s discretion, reasonable attorney’s fees and costs. If the landlord acted willfully or with fraud, oppression, or malice, a court can award up to three times the overcharge in damages.⁴

The statute of limitations is three years from the date of the overcharge. City attorneys and county counsel can also bring enforcement actions, and the statute presumes a tenant suffers irreparable harm from a violation, which makes injunctive relief easier to obtain. Any lease clause asking a tenant to waive these protections is void as against public policy.⁴ The California Attorney General’s office recommends getting legal assistance promptly, including free help through LawHelpCA.org if cost is a concern.⁸

The 2030 Sunset

Section 1947.12 is scheduled to be repealed on January 1, 2030.⁴ Unless the legislature extends or replaces it, the statewide cap stops applying to covered properties after that date. Independent local rent control ordinances would continue to govern the units they already cover. Every figure and procedure above applies through that sunset date.

1
California Legislative Information. California Civil Code 1947.12
2
California Department of Justice Office of the Attorney General. The Tenant Protection Act Your Obligations as a Landlord or Property Manager
3
U.S. Bureau of Labor Statistics. Consumer Price Index, Los Angeles Area – April 2026
4
California Legislative Information. California Code CIV 1947.12
5
Los Angeles County Department of Consumer and Business Affairs. Rent Increases – Consumer and Business
6
California Legislative Information. California Code CIV 827 – Change of Terms of Lease
7
California Legislative Information. California Code CCP 1013
8
California Department of Justice. Landlord-Tenant Issues