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How many smoke alarms does an apartment need? Calculator and the 60 m² rule with examples
In short
An apartment must have at least one smoke alarm for each beginning 60 square metres of each floor or level (Ministry of the Interior decree 300/2025, section 1). A 75 m² apartment on one floor therefore needs at least two. SPEK also recommends an alarm in every bedroom, the hallway and the living room, and on every floor near the stairs.
In short
An apartment must have at least one smoke alarm for each beginning 60 square metres of each floor or level (Ministry of the Interior decree 300/2025, section 1). A 75 m² apartment on one floor therefore needs at least two. SPEK also recommends an alarm in every bedroom, the hallway and the living room, and on every floor near the stairs.
What the decree says (sections 1 and 3)
The number and placement come from the Ministry of the Interior decree on smoke alarms (300/2025), in force since 1 January 2026. As the building owner, the housing company is responsible for there being enough working smoke alarms in the apartments (Rescue Act 379/2011, section 17, as amended by Act 436/2023).
300/2025 · section 1(1)An apartment must have at least one smoke alarm for each beginning 60 square metres of each floor or level of the apartment. (Unofficial translation.)
300/2025 · section 3When placing smoke alarms, the shape and ventilation of the room and the audibility of the alarm sound must be taken into account. Smoke alarms must be installed on the ceiling unless the properties of the alarm prevent it. They must be placed at least 0.5 metres from walls and wall-like structures. (Unofficial translation.)
What the decree does not say
- It does not say which area is meant. The calculator uses the number you enter.
- It has no bedroom rule. Bedrooms come from SPEK's recommendation.
- The Rescue Act does not require mains-powered, interlinked or remotely read alarms, nor alarms in, for example, the shared spaces of a block of flats (Ministry of the Interior).
The minimum is not always enough. By law an apartment must have enough alarms to detect a beginning fire as early as possible. According to SPEK, one smoke alarm is rarely enough in a 60 m² apartment.
Examples: 58 m², 75 m², 121 m² and two floors
The minimum is counted floor by floor: divide the floor's area by 60 and round up. Then add the floors together.
| Apartment | At least (decree) | SPEK's recommendation |
|---|---|---|
| 58 m², one floor, 2 rooms | 1 | 3 |
| 75 m², one floor, 3 rooms | 2 | 4 |
| 121 m², one floor, 4 rooms | 3 | 5 |
| Terraced house 50 + 40 m², 3 rooms | 1 + 1 = 2 | 5 |
| Exactly 60 m², one floor | 1 | – |
| 61 m², one floor | 2 | – |
| Two floors 61 + 59 m², 4 rooms | 2 + 1 = 3 | 6 |
| Large studio 65 m², 1 room | 2 | 1 |
121 m² is two full 60 m² blocks and one square metre more. A beginning block needs its own alarm, so the result is 3.
In a two-floor apartment the floors are counted separately. 120 m² on one floor is 2, but split 61 + 59 m² it is 2 + 1 = 3.
In a large studio the decree requires more than SPEK's calculator gives. Then the decree applies.
The minimum or SPEK's recommendation?
The decree's minimum is binding. SPEK's recommendation is not law but guidance from the Finnish National Rescue Association. It is based on rooms: an alarm in every bedroom, in the hallway (the escape route), in the living room and on every floor near the stairs.
The SPEK numbers here are the same as in SPEK's own calculator: for example 4 for a three-room apartment and 5 for a three-room apartment on two floors. SPEK itself says its calculator is indicative, because floor plans vary.
Judging the sufficient number and the right placement is up to the housing company. So look at both numbers and at the apartment's floor plan.
Does a bedroom need a smoke alarm?
The decree has no bedroom rule, so the law does not directly require an alarm in every bedroom. SPEK does recommend it. It says people are at special risk while asleep, so it is important to have a smoke alarm in every bedroom. The recommendation is not law, but it is a good reason for extra alarms.
Count a whole building
Count all apartments at once. Type or paste one apartment per line as apartment; m² floor 1; m² floor 2; rooms. You can copy the columns straight from Excel.
Format: apartment; m² floor 1; m² floor 2; rooms
Number of smoke alarms by apartment
Type at least one apartment first.
The building mode runs on JavaScript in your browser. Without it, the free Excel template gives the same numbers: it uses the same formula.
Download the Excel template (same formula)Frequently asked
Per floor. Under the decree there must be at least one alarm for each beginning 60 square metres of each floor or level of the apartment. Each floor is counted separately and the results are added together. If the apartment has, for example, a loft used as living space, it is safer to count it as a level of its own.
The one you enter. The decree does not say whether it means the apartment's floor area or something else. Housing companies usually use the apartment area shown, for example, in the property manager's certificate. If the area is right at the 60 m² limit, rounding up is the safer choice.
One alarm meets the decree's minimum if the apartment is on one floor and at most 60 m². According to SPEK, however, one smoke alarm is rarely enough in an apartment of this size. If the only alarm fails, the apartment is left with no alarm at all.
Other free tools
All tools- Template Maintenance plan A one-page plan: responsibilities, testing, batteries, faults and records. Fill in and print, or download the Word file.
- Notice Resident notice A ready notice for the stairwell: how to test the alarm and where to report a fault.
- Excel Inspection log and register An Excel template for apartments, alarms, tests and faults. It works out the minimum number itself.
Read also
Sources
- Ministry of the Interior decree on smoke alarms 300/2025 (Finlex, in Finnish) · checked 12 Oct 2026
- Rescue Act 379/2011, section 17 (Finlex, in Finnish) · checked 12 Oct 2026
- SPEK: number of smoke alarms and calculator (in Finnish) · checked 12 Oct 2026
- SPEK: the housing company's responsibility, Q&A (in Finnish) · checked 12 Oct 2026
- Ministry of the Interior: FAQ on smoke alarms (in Finnish) · checked 12 Oct 2026
When Excel and paper are no longer enough.
Alarmi reminds residents by email to test their alarms, collects the confirmations and shows which apartments have not answered. Alarmi is not a device and is not connected to the alarms. Responsibility for working order stays with the housing company.
