Rent increase 2026: how much can rent be raised and when

The increase is based on what has been agreed

Under the Act on Residential Leases, the rent is determined by what has been agreed. The Act has no euro or percentage limit on how much rent may be raised. What is decisive is the increase clause in the lease, for example a link to the cost-of-living index or a fixed annual percentage.

A term under which the landlord could raise the rent at its discretion without an agreed basis is void under the law. So first check the contract for the basis of the increase, the date from which it is calculated and how often increases are made.

If the contract has no increase clause

If a fixed-term lease has no increase clause, the landlord cannot unilaterally decide on a new rent. Changing the rent can be agreed between the parties, and it is advisable to put the agreement in writing.

Under the law in force from 1.10.2026, a court may, at the landlord's request, raise the rent or change a term governing how the rent is determined if the rent is unreasonable within the meaning of section 36 of the Contracts Act. Likewise, a tenant may demand that an unreasonable rent be adjusted. While the tenant's adjustment claim is pending in the district court, the landlord may not terminate the lease.

What the 1.10.2026 reform changed

After the legislative amendment (531/2026), a rent increase must be notified to the tenant in writing. The increase takes effect at the earliest one month after the notice, from the start of the next rent payment period. The increased rent may not be collected retroactively. At the tenant's request, the landlord must promptly and free of charge explain the grounds for the increase and how the new rent is calculated.

Previously, a rent increase clause could be worded so that the tenant had to start paying the increased rent on their own, without a separate notice (KKO 2016:5). This is no longer possible in new contracts.

Does the change apply to your existing contract

The new law generally also applies to contracts made before 1.10.2026. However, the entry-into-force provision contains exceptions, one of which is section 27 on the determination of rent. Contracts made before the law entered into force remain subject to its earlier wording, unless the parties agree otherwise after the law entered into force.

In practice, the new notification rules apply to contracts made on or after 1.10.2026. In an old contract the increase is made according to the terms of the contract, and the term may still be such that the increase takes effect without a separate notice. However, the new provisions on court adjustment apply to old contracts as well. For an overview of other legislative changes, see the Rental Radar guide Rental agreement 2026.

Checking the index increase

Many increase clauses are tied to Statistics Finland's cost-of-living index (1951:10=100). An index increase is usually calculated as follows: new rent = current rent × new index point figure / base index point figure. The contract specifies which month's index is used as the base index and as the adjustment index.

The latest cost-of-living index reading is from September 2026: 2401. The annual change in consumer prices, i.e. inflation, was 2.5% in September (Statistics Finland, 14.10.2026). For comparison, free-market rents rose by an average of 0.1% year on year in July–September 2026. Also check whether the contract has a minimum increase, such as a fixed percentage, that applies even if the index rises less.

Find the base index month and index figure in the contract
Look up the index figure for the review month on Statistics Finland's website
Calculate the new rent and compare it with the one notified
Check that the increase is made at the agreed time

Template: message to check an increase

If the increase seems incorrect, ask the landlord in writing for a calculation. The text below is a template whose names are fictional. Replace the parts in square brackets with your own details and keep a copy of the message.

Template: Request to clarify the grounds for a rent increase

To: [landlord's name], [email / address]

Sender: Matti Meikäläinen, [address], [phone]

Rental property: [street address and apartment], lease made on [date].

On [date] I received a notice that the rent will rise from [current rent] euros to [new rent] euros starting [date].

I request a written explanation of the grounds for the increase and of how the new rent is calculated: the base index used and its index points, the review index and its index points, and the contract term applied.

According to my own calculation, based on [clause] of the agreement, the new rent would be €[amount]. I request an explanation before the first due date of the increased rent [date].

[Place and date] – Matti Meikäläinen

Where to get help

If the landlord is a business, the tenant can ask for advice from the KKV consumer advisory service and take the dispute to the Consumer Disputes Board. In tenancies between private individuals, help is available from legal aid offices and from tenants' and landlords' organisations. In Rental Radar you can see the rent level for your area, which you can use to help assess reasonableness.

Frequently asked questions

How much can rent be raised per year?

The law sets no percentage limit. The increase is made according to the increase clause in the tenancy agreement. As a last resort, an unreasonable rent can be challenged by asking a court to reduce it.

How far in advance must a rent increase be notified?

In agreements made on or after 1.10.2026, an increase must be notified in writing and takes effect at the earliest from the start of the rent payment period following one month after the notice. Older agreements are governed by the contract term and the earlier law.

What is the latest point figure of the cost-of-living index?

In September 2026 the cost-of-living index (1951:10=100) stood at 2401 (Statistics Finland 14.10.2026).

Rental Radar brings together the topic's figures, deadlines and services. Open Rental Radar →

Calculate it yourself

Ready-made tools

Landlord's calculation and document templates · Rental yield calculation and 9 Word templates: termination, rent increase, warning, deposit, move-out inspection
Moving checklist · Moving tasks on a timeline from 8 weeks out to moving day

Sources

The article is general information and does not replace the guidance of an authority, a lawyer or an adviser. Check up-to-date information from the sources.

Other guides

Other free templates and bases

All templates and forms →