The estimated number of Palestinians at the end of 2021 was about 14 million: 5.3 million in the State of Palestine (3.2 million in the West Bank and 2.1 million in the Gaza Strip), 1.7 million in the 1948 territories, and nearly 7 million in the diaspora (6.3 million live in Arab countries and 750,000 in foreign countries). The following is a description of Palestinian demographics in the State of Palestine.
More than one-third of the population of the State of Palestine is under 15 years of age. Those 0-14 years old constitute an average of 38 percent of the total population at the end of 2021 (36 percent in the West Bank and 41 percent in the Gaza Strip). The percentage of the elderly population aged 65 years and above reached an average of 3 percent of the total population in Palestine (4 percent in the West Bank and 3 percent in the Gaza Strip).
https://arabcenterdc.org/resource/brief-report-on-the-population-of-palestine-at-the-end-of-2021/