At the end of 2017, the 37,857 household-dwelling units (later: households) with a head i.e. a reference person with foreign background in Helsinki made up 11.4 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 Finnish background. In the following statistics, the origin of the reference person determines the origin of the whole household. The largest group of households with foreign background was those with Russia as their background country, making up almost a quarter of all households with foreign background, followed by Estonian households with a share of 14 per cent and Somali households with a share of 7 per cent.
Households with foreign background are, on average, larger than households with Finnish background. One-person households comprised 36 per cent of the former and half of the latter. Furthermore, 9 per cent of households with foreign background had five or more members while only about 2 per cent of households with Finnish background were that large.