Rent increase calculator
New rent or percent increase, checked against a rent cap if one applies.
The CPI is a number you type from your state's or rent board's official figure; 3.5% is only an example. Exemptions and local rules are not checked.
How do I calculate a rent increase?
Percent increase = (new rent ÷ current rent − 1) × 100. New rent = current rent × (1 + percent ÷ 100). Example: $2,000 raised by 5% is $2,100, an increase of $100 a month or $1,200 over a year. Going from $2,000 to $2,250 is 12.5%. The calculator does both directions and shows what the change adds up to in a year.
How does California limit rent increases?
For housing the law covers, California Civil Code section 1947.12(a)(1) says an owner may not, over any 12-month period, raise the gross rental rate by more than 5 percent plus the percentage change in the cost of living, or 10 percent, whichever is lower. The increase is measured from the lowest gross rental rate charged for the unit in the 12 months before, and rent discounts or credits the tenant accepted are left out of that comparison. The California Attorney General's page on rent caps says the statewide cap applies to most rental housing more than 15 years old, and that the cost-of-living figure is taken from April consumer price index data; local ordinances can be stricter. The statute as we read it excludes housing issued a certificate of occupancy within the previous 15 years and has an end date of January 1, 2030, so check that it still applies and which exemptions fit your unit. Example with a CPI change of 3.5%, which is an input, not a forecast: the cap is 8.5%, so $2,000 can rise to $2,170; a 5% increase is allowed and a 12.5% one is not. With a CPI change of 6% the 10% ceiling applies and the cap is 10%.
How does Oregon limit rent increases?
Oregon's rule is in ORS 90.323 and 90.324. After the first year of a tenancy, a landlord may raise rent no more than once in any 12-month period, with at least 90 days of written notice, and by no more than the percentage the state calculates under ORS 90.324: the lesser of 10 percent or 7 percent plus CPI, where CPI is the September annual 12-month average change in the Consumer Price Index for All Urban Consumers, West Region. The Department of Administrative Services publishes the figure for each coming calendar year by September 30, so look up the current number and type its CPI into the calculator. A dwelling whose first certificate of occupancy was issued less than 15 years before the notice is not subject to the percentage limit, and a landlord who breaks the limit owes the tenant three months' rent plus actual damages. Example: with a CPI of 3.5% the cap is 10% and $2,000 can rise to $2,200.
How much notice do I have to give?
It depends on the state, the lease and the size of the increase. Under California Civil Code section 827(b), a written notice must be delivered at least 30 days before the effective date if the increase, with any others in the previous 12 months, is 10 percent or less of the rent charged in that period, and at least 90 days if it is more than 10 percent. Under Oregon's ORS 90.323 the notice is 90 days (7 days for a week-to-week tenancy), and it must state the amount of the increase, the new rent and the effective date. The calculator shows these two when you choose California or Oregon. For anywhere else, read your state's statute and your lease; we do not give a table because we verified only these two statutes.
What about other states and cities?
Rules differ widely. Some states and cities cap annual increases, many limit nothing but notice, and some local rent ordinances are stricter than their state's law. We deliberately do not list every state: a table of caps goes out of date each year, and we only publish rules we have checked against the statute. Look up your state's landlord-tenant statute and your city or county ordinance, or ask your state attorney general's office or a local landlord association. If your rule is a base percentage plus CPI with a ceiling, choose the custom rule and enter the base, the ceiling and the CPI.
Where do I get the CPI number?
The consumer price index comes from the U.S. Bureau of Labor Statistics. Which index, region and month count depends on the law: Oregon uses the West Region CPI-U for September; California's rent cap uses a regional figure drawn from April data according to the Attorney General. Use the exact figure your state or local rent board publishes rather than the national headline number, and type it as a percentage. If you use the wrong index, the cap can be off by a point or more.
What are common mistakes with rent increases?
Counting from the wrong rent: California measures from the lowest rate charged in the previous 12 months, so a rent cut or a temporary discount you gave can lower the base. Forgetting earlier increases: two small increases in 12 months can add up to more than the cap, and California's notice period counts all increases in the window. Assuming a unit is exempt without checking the date of its certificate of occupancy or the specific exemption in the statute. Giving too little notice; the statutes above set minimums. And treating this calculator as legal advice: it does the arithmetic; the statute decides.
For planning only — not legal advice. Laws change, have exemptions and differ by city; ask your attorney or local rent board. Sources, checked October 28, 2026: California Civil Code sections 1947.12 and 827; California Attorney General, “Rent Caps” (oag.ca.gov/rentcaps); Oregon Revised Statutes 90.323 and 90.324 (oregonlegislature.gov). See also the prorated rent calculator, rent affordability calculator, rental property calculator and inflation calculator. How we check our calculators.