At the end of 2016, the 34,573 household-dwelling units (later: households) with a head i.e. a reference person with a foreign mother tongue in Helsinki made up 10.6 per cent of all households in the city. The reference person of a household is primarily the household member with the highest income. Other household members may have a different mother tongue. In the following statistics, the mother tongue of the reference person determines the mother tongue of the whole household. The largest group of households with a foreign mother tongue was those with Russian as their home language, making up almost a quarter of all households with a foreign mother tongue, followed by Estonian-speaking households with a share of 14 per cent and Somali-speaking  households with a share of 7 per cent.

Households with a foreign mother tongue are, on average, larger than households with a national mother tongue. One-person households comprised 35 per cent of the former and half of the latter. On the other hand, 9 per cent of households with a foreign mother tongue had five or more members while only about 2 per cent of households with a national mother tongue were that large.