How to Calculate a Rent Increase (Percentage, Monthly and Yearly)

By the SAA Tool editor, an IT support engineer · Last reviewed 1 October 2026 · 6 min read

A rent increase notice usually gives you either a percentage or a new figure, rarely both. Being able to turn one into the other, and to see what the change costs over a whole year, makes it much easier to check the sum and decide whether the rise is fair, or even allowed where you live. Here are the formulas, worked examples in several currencies and a look at how four very different places limit rent rises.

The two basic sums

If you know the percentage, multiply:

New rent = Current rent × (1 + increase ÷ 100)

A rent of 1,500 a month rising by 4% becomes 1,500 × 1.04 = 1,560. That's 60 more a month, or 720 more a year.

If you know the new rent, work out the percentage:

Increase % = (New rent − Current rent) ÷ Current rent × 100

A flat going from €1,200 to €1,290 a month has risen by 90 ÷ 1,200 × 100 = 7.5%. Always divide by the old rent, not the new one. Dividing by €1,290 would give 6.98% and understate the rise.

Monthly and yearly figures

A rise that sounds small per month can be a large percentage, and a big yearly figure can hide a modest percentage. It helps to look at both.

• "Only £100 more" on a £1,250 monthly rent is 100 ÷ 1,250 = 8%, and £1,200 more over a year.
• A £1,350 rent going to £1,450 is a 7.41% rise, again £1,200 a year.
• Some leases quote rent per year. AED 85,000 a year rising by 5% becomes AED 89,250: AED 4,250 more a year, or about AED 354.17 a month.

When you budget, think in the yearly figure. It's the real extra cost of staying another year.

Rises over several years add up faster

Each rise is worked out on the rent you already pay, including the previous rises, so repeated increases compound. Here is a 1,500 monthly rent going up 4% every year:

So five rises of 5% add up to 27.63%, not 25%. Going the other way, if a rent went from 1,000 to 1,210 over two years, the average rise was 10% a year, not 10.5%:

Average yearly rise = (New rent ÷ Old rent)^(1 ÷ years) − 1

This is the same maths as savings growing with interest, which our guide to how compound interest works explains in more detail.

Legal limits: four very different examples

How much rent can rise, how often and with how much notice depends on the country, the city, the type of home and often the contract. Some places cap the percentage, some tie it to inflation or a rent index, and some have no fixed cap but control the process. These four examples show the range. They were checked against official pages when this guide was reviewed, and rules like these are changed from time to time.

Ontario, Canada: a yearly guideline

Ontario publishes a rent increase guideline based on the Ontario Consumer Price Index and capped at 2.5%. It is 2.1% for 2026 (it was 2.5% for 2025). Rent can go up only if at least 12 months have passed since the last increase or the start of the tenancy, and the landlord must give written notice in the proper form at least 90 days before. The guideline doesn't cover some homes, including new buildings, additions and most new basement flats first lived in after 15 November 2018. For a covered C$2,000 rent in 2026, the guideline allows up to 2,000 × 1.021 = C$2,042.

California, US: a cap linked to the cost of living

Under California's Tenant Protection Act, as summarised by the state Attorney General, rises in any 12-month period are capped at 5% plus the percentage change in the cost of living, with a maximum of 10%. If the cost-of-living figure for your area were 3%, the cap would be 8%, so a $2,400 rent could go up to $2,592 at most. Some homes are exempt, including units built within the last 15 years and certain single-family homes and condos, and some cities have stricter local rent control.

England, UK: once a year, with a market-rent test

Under the Renters' Rights Act, from 1 May 2026 a rent increase proposed in a Section 13 notice can't take effect until at least 52 weeks after the last increase, and the landlord must give the notice at least two months before the rise is due. There is no fixed percentage. Instead, if you think the new rent is higher than the open market rent, you can challenge it at the First-tier Tribunal, as the government's guide for tenants explains. Scotland, Wales and Northern Ireland have their own rules.

Dubai, UAE: tied to the average rent for similar homes

Decree No. 43 of 2013 links the maximum rise to how far your rent is below the average rent for similar properties:

If you pay AED 80,000 a year and the average for similar homes is AED 100,000, your rent is 20% below average, so the most it can rise is 5%, to AED 84,000.

How to check a rise with our calculator

The Rent Increase Calculator works in your browser and does both sums, per month and per year.

1. Type your Rent now and choose Per month or Per year under Paid.
2. Under I know, choose The increase in % and fill in Increase (%), or choose The new rent and fill in New rent.
3. With a percentage, pick 3 years, 5 years or 10 years under Show years to see the same rise repeated each year.
4. If a limit applies to you, type it in Legal or contract limit % (optional), and choose your Currency.
5. Read New rent a month, Change a month and Increase (or the yearly versions), then the table with Change a year, Current rent a year and New rent a year.

For example, a 2,000 monthly rent going to 2,070 is a 3.5% rise. With a limit of 2.1% entered, the calculator warns that the rise is above the limit by 28 a month.

Be clear about what it can't do. It doesn't know any local law: it compares your figures with the single percentage you type. It can't look up a rental index average or a cost-of-living figure, and it doesn't check notice periods or dates. The years table assumes the same percentage every year.

For a quick one-off check, the Percentage Calculator has a "Percentage change from X to Y" line. And if you're putting money aside each month to cover future rises, the Compound Interest Calculator shows how those savings grow.

Before you agree: a checklist

• Check the sum both ways. Work out the percentage and the extra cost a year.
• Check the dates. When was the last rise, when did the notice arrive and when does the new rent start?
• Read your contract. Some leases fix the rent for a period or set out how reviews work.
• Find the local rule. Look for the official housing or rent authority where you live, not a forum post.
• Compare with similar homes. Listings nearby or an official index show whether the new rent is in line.
• Get it in writing. Ask for the new rent, the start date and the payment schedule in writing.
• Ask about a trade-off. Landlords sometimes accept a smaller rise for a longer tenancy.

This guide is general information, not legal or financial advice. Rent rules change and differ by country, region and contract, so check the official rules where you live, and speak to a tenant advice service or a lawyer about your own case.

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