In 1750, when Finland was part of the Duchy of Sweden, and had a total population of just 422 thousand. Over the next 55 years the population grows steadily and reaches 896 thousand people, before it drops to 863 thousand in 1810. The Finnish borders did expand during the early 1800s, adding 12,000 people in 1809 and 185 thousand in 1811, however the dip in the graph most probably occurs as a result of the Finnish War, fought between Sweden and Russia in 1808 and 1809, and this war resulted in Finland becoming a part of the Russian Empire. From 1810 to 1865 the population then grows steadily again, until 1870 when it dips again from 1.84 million to 1.77 million. This second dip in population size is due to the Finnish famine of 1866-68, which resulted in the fatalities of around 8.5% of the entire Finnish population.

Throughout the twentieth century and until now the population has grown with each entry in the graph. Finland gained independence in 1918 after a brief civil war, and it was also heavily involved in fighting against Russia in World War II, and between 85 and 90 thousand people (2.3 to 2.6 percent of the total population) are estimated to have died as a direct result of the war. In spite of this the population has grown at a consistent rate (although the graph appears skewed as the intervals change from 10 years to 5 years in 1950), and the total population is expected to reach 5.5 million in 2020

As of 2024, the total population of Finland was approximately 5.64 million inhabitants. In the period from 1915 to 2024, the population of Finland steadily increased, but showed a slowing trend in recent years. In 1950, the total population was around four million, and it took until 1990 to reach the 5 million mark.

During the Second World War, the three Axis powers of Germany, Italy, and Finland mobilized the largest share of their male population. For the Allies, the Soviet Union mobilized the largest share of men, as well as the largest total army of any country, but it was restricted in its ability to mobilize more due to the impact this would have on its economy. Other notable statistics come from the British Empire, where a larger share of men were drafted from Dominions than from the metropole, and there is also a discrepancy between the share of the black and white populations from South Africa.

However, it should be noted that there were many external factors from the war that influenced these figures. For example, gender ratios among the adult populations of many European countries was already skewed due to previous conflicts of the 20th century (namely WWI and the Russian Revolution), whereas the share of the male population eligible to fight in many Asian and African countries was lower than more demographically developed societies, as high child mortality rates meant that the average age of the population was much lower.