In 2018, the number of children born in Helsinki was 6,388. To each one thousand 15–49-year-old women in the city, 38 children were born. This figure, the crude birth rate (fertility rate), was 34 for Finnish-, Sami- or Swedish-speaking women and 56 for women with a foreign mother tongue.

On average, mothers with a foreign mother tongue bore their children at a younger age than mothers who spoke one of the national languages. Among 20–24-year-olds, the fertility rate was 56 for women with a foreign mother tongue and 10 for Finnish- and Sami-speaking women. The fertility rate of Finnish- and Sami-speaking women was somewhat lower than that of foreign-language speakers among other age groups as well.

In 2018 the total fertility rate in Helsinki was 1.14. For the population with a foreign mother tongue, the figure was 1.65.

Fertility varies with language group. Of large language groups, the fertility rate of Russian-, Estonian- and English-speaking people differs very little from that of the population with a national mother tongue. On the other hand, the total fertility rate of Somali-, Arabic- and Kurdish-speaking residents was over two times higher than that of the whole population. In all, the fertility of foreign-language speakers has fallen in the 2000s, while that of the population with a national mother tongue has remained more constant.