Rent increase calculator: percent, new rent and your state's cap

This rent increase calculator turns a landlord's letter into numbers you can act on: the dollar and percent increase, the yearly cost, whether it sits inside your state's cap, and how much notice you are owed. It runs in your browser and uses the caps published by California, Oregon, Washington and New York as of today, with a custom option for anywhere else.

How to use the rent increase calculator

Type your current rent and the new rent from the notice, or switch to percent if that is all the letter gives. Pick where the rental is. A state that is not listed has no statewide cap; choose "Custom cap" if your city has rent control and you know the figure. Take-home pay is optional and drives the rent-to-income line. Results update as you type, and "Copy summary" gives you plain text to paste into an email or a letter to the landlord.

How it works: the method and the rent increase percentage formula

Three sums, all of which you can check by hand.

• Monthly increase = new rent minus current rent.
• Percent increase = monthly increase divided by current rent, times 100.
• Yearly cost = monthly increase times 12.

In percent mode the tool runs the first sum backwards: new rent = current rent times (1 + percent / 100). The projection table compounds the same percent each year. Treat it as a "what if", not a forecast.

The cap check compares your percent with the limit for the place you picked. The limits come from the statutes and official annual notices, checked on the day this post was written:

Place	Cap used by the tool	How it is set	Source
California, Los Angeles and Orange County	8.7%	5% plus April metro CPI (3.7%), never above 10%. For increases effective 1 August 2026 to 31 July 2027.	Civil Code 1947.12, BLS CPI-U Los Angeles
California, San Francisco Bay Area	8.8%	5% plus April CPI 3.8%	BLS CPI-U San Francisco
California, San Diego	8.2%	5% plus March CPI 3.2% (March is used where April is not published)	BLS CPI-U San Diego
California, Riverside and San Bernardino	8.1%	5% plus March CPI 3.1%	BLS CPI-U Riverside
California, all other counties	8.6%	5% plus the state's own April CPI (3.6%)	California DIR CPI table
Oregon	9.5% for 2026 (10% from 1 January 2027)	Lesser of 10% or 7% plus CPI; none in the first year of a tenancy	Oregon Office of Economic Analysis, ORS 90.323
Washington	9.683% for 2026 (10% for 2027)	Lesser of 10% or 7% plus Seattle CPI; none in the first 12 months	Washington Commerce, HB 1217, RCW 59.18.140
New York, Good Cause areas	8.38% (NYC and listed downstate counties) or 8.15% (other opted-in places)	Lesser of 10% or 5% plus CPI; above that is presumed unreasonable, not banned	NY Homes and Community Renewal, RPL 226-c for notice

Notice periods come from the same statutes: California Civil Code 827 (30 days for 10% or less, 90 days above that), Oregon ORS 90.323 (90 days), Washington RCW 59.18.140 (90 days) and New York RPL 226-c (30, 60 or 90 days depending on how long you have lived there, for increases of 5% or more). The rent-to-income line flags 30% because HUD defines cost-burdened households as those paying more than 30% of income for housing.

Two limits. Caps have exemptions (new buildings, some single-family homes, subsidized units, small landlords in New York), and cities such as Los Angeles, San Francisco, Portland and New York City add stricter local rules. "Inside the cap" does not make an increase legal and "above the cap" does not make it void; the result tells you which question to ask next.

A worked example with the arithmetic

This is an example, not a real tenancy. A tenant in Portland, Oregon pays $2,000 a month. The landlord's letter proposes $2,300 from 1 February 2027.

• Monthly increase: 2,300 minus 2,000 = $300.
• Percent: 300 divided by 2,000 = 0.15, so 15%.
• Yearly cost: 300 times 12 = $3,600.
• Cap check: the increase takes effect in 2027, when Oregon's maximum is 10%. The most the rent can rise to is 2,000 times 1.10 = $2,200. The proposed $2,300 is $100 a month, or $1,200 a year, over the cap. (Select "Custom cap" and type 10 to run this; the Oregon option uses the 2026 figure until the year turns.)
• Notice: Oregon requires 90 days in writing, so a letter dated after 3 November 2026 cannot take effect on 1 February.
• Rent-to-income: on $5,500 take-home, rent goes from 36.4% to 41.8% of income. Both are above HUD's 30% line.

Under ORS 90.323 a landlord who raises rent above the cap owes the tenant three months' rent plus actual damages, so a short, polite letter quoting the statute usually gets the number corrected.

What good looks like, and what to do next

An increase at or below CPI (3% to 4% in most metros this year, per the BLS figures above) is a landlord passing on costs. In the 5% to 10% band, ask what changed and whether a longer lease would hold the number. Above 10% in a capped state, quote the statute back. With no cap, your levers are the lease, the notice period, the local market and your willingness to move.

Whatever you decide, put it in writing and keep the notice and the dated calculator summary. Ask for the increase to be phased, trade a longer lease for a smaller rise, or ask for a repair in exchange. If the increase breaks the cap or the notice period, say so once, cite the section, and give a date for a corrected notice. Our guide to handing life admin to ChatGPT shows how to get a first draft of that letter in two minutes. If your pay has not kept up, the salary increase calculator shows what a raise is worth after inflation and tax, and the electricity cost calculator finds the household bills to blame.

FAQ

How do I calculate a rent increase percentage?

Subtract the old rent from the new rent, divide by the old rent, then multiply by 100. A rise from $1,800 to $1,950 is 150 divided by 1,800, which is 0.0833, so 8.33%. Going the other way, $1,800 times 1.05 is $1,890 for a 5% increase. The calculator above does both and adds the yearly cost.

How much can a landlord raise rent in California in 2026?

For most housing more than 15 years old, Civil Code 1947.12 limits increases over any 12 months to 5% plus the regional April CPI, with a ceiling of 10%. For increases effective from 1 August 2026 that is 8.7% in the Los Angeles area, 8.8% in the Bay Area, 8.2% in San Diego, 8.1% in Riverside and 8.6% elsewhere. City rent control can set a lower limit.

What is the maximum rent increase in Oregon and Washington?

Both states use the lesser of 10% or 7% plus CPI. Oregon's published maximum is 9.5% for 2026 and 10% for 2027; Washington's is 9.683% for 2026 and 10% for 2027. Neither allows an increase in the first year of a tenancy, both require 90 days' written notice, and both exempt newer buildings. Oregon's Office of Economic Analysis and Washington's Department of Commerce publish the figures.

How much notice does a landlord have to give for a rent increase?

It depends on the state and the size of the increase. California requires 30 days for increases of 10% or less and 90 days above that. Oregon and Washington require 90 days. New York requires 30, 60 or 90 days for increases of 5% or more, depending on how long you have lived there. Elsewhere, the lease and the general rule for changing a month-to-month tenancy apply, often 30 days.

What percent of income should rent be?

HUD treats households that pay more than 30% of income for housing as cost burdened, and more than half as severely burdened. That is a planning benchmark rather than a rule, and plenty of people in expensive cities pay more. The calculator shows your share before and after the increase so you can see how far it moves you toward or past that line.