Legal Rent Increase Cap Calculator

This page answers what your jurisdiction permits, not what your landlord has proposed. It starts from the local inflation figure and works out the ceiling. If you already know the increase and want to see where the rent lands over several renewals, the rent increase calculator projects a rate you supply.

Legal rent increase percentage calculation requires understanding both the mathematical formula for percentage increases and the jurisdiction-specific legal caps that limit how much a landlord can raise rent in any given period.

New rent after increase formula: New Rent = Current Rent × (1 + Increase Rate)

Increase percentage from old and new rent: Increase % = ((New Rent − Old Rent) ÷ Old Rent) × 100

Rent control caps - key approaches by jurisdiction:

CPI-based limits (most common): Many cities cap rent increases at local Consumer Price Index (CPI) inflation, typically 3–8% annually. Max Increase = CPI% (or CPI% + fixed buffer, e.g. CPI + 5%)

California AB 1482 (statewide, 2020+): Max increase = lower of (CPI + 5%) or 10% per year. Local rent control ordinances (Los Angeles, San Francisco, Oakland) often set lower caps (3–4%).

Oregon statewide (2019+): Max increase = CPI + 7%, not to exceed 10%.

New York City: Rent Stabilized apartments: 1-year lease ~3%, 2-year lease ~2.75%. The Rent Guidelines Board sets these annually, so they change every year.

Required notice periods:

• Less than 10% increase: typically 30 days notice
• 10% or more increase (where allowed): typically 60–90 days notice
• Always check local landlord-tenant law, which varies significantly by state and city

Cumulative increases - the compound effect: Rent After N Years = Initial Rent × (1 + Annual Rate)^N

A 5% annual increase compounding for 5 years: Initial Rent × (1.05)^5 = Initial Rent × 1.276 (27.6% total increase)

Worked example: Current rent: $1,800/month. Local CPI: 4.2%. Jurisdiction allows CPI + 2% or 8% maximum.

• Allowable increase: min(4.2% + 2%, 8%) = min(6.2%, 8%) = 6.2%
• New rent: $1,800 × 1.062 = $1,911.60/month
• Increase in dollars: $111.60/month = $1,339.20/year
• Notice required: 30 days (less than 10% increase)
• In 5 years at the same rate: $1,800 × (1.062)^5 = $1,800 × 1.350898 = $2,431.62/month

The hard cap did nothing in that example, because CPI plus the buffer already came in under it. That is the usual case in a low-inflation year. The cap only starts to bite when CPI runs hot, which is exactly when tenants need it, and it is why California’s ordinance is written as the lower of two numbers rather than as a single figure.

Setting the inputs for your own jurisdiction:

• California (AB 1482): buffer 5%, hard cap 10%
• Oregon: buffer 7%, hard cap 10%
• A city with a straight CPI ordinance: buffer 0%, hard cap 0 (meaning none)
• No rent control at all: put your expected market increase in the CPI box, buffer 0, cap 0

Always verify your local rent control ordinance before issuing any increase notice. Violations can result in tenant rights claims and required rent reductions, and several ordinances also require the increase to be refunded.