The Palestine Authority Central Bureau of Statistics has published a statistic that there are now 12.2 million Palestinians worldwide. This is an absurd over-estimate. Add it up yourselves. the Palestinian estimates of their population in the West Bank and Gaza were over-estimated by ca. 1 million. They did this by exaggeration and counting people twice (for example in Jerusalem and the West Bank). According to Israeli statisticians, the total comes to 1.5 million in Gaza and 2.4 million in the West Bank, totalling 3.9 million. The UNRWA estimates also agree with these figures.
The number of Palestinians in various Arab countries could be estimated from UN estimates of so-called “refugees.” This is mainly because the various Arab countries, except for Jordan, refused to give the Palestinians living there citizenship. According to UNRWA estimate there are 455,000 Palestinians in Lebanon, just over 2 million in Jordan, but since they are all Jordanian citizens they don’t really count, and over 500,000 in Syria, but since at least half of these have been dispersed to Turkey, Lebanon, Jordan and Iraq, that leaves only about 250,000. In Iraq the number of Palestinians has decreased significantly since the overthrow of Saddam Hussein and now amounts to only ca. 10,000. There are no Palestinians in Kuwait (they were all killed or expelled after the First Gulf War) and they are not allowed to stay in Saudi Arabia and the Gulf States. There are very few Palestinians in Egypt, there used to be ca. 50,000 but many of these were expelled partly because the Egyptian Government has very bad relations with Hamas in Gaza. If we add all these Palestinians in Arab countries together we get a maximum of ca. 3.5 million.
There are Palestinians in Europe (ca. 100,000) and North (ca. 200,000) and South America (ca. 250,000), the total is ca. 500,000, and most of these are Christians who have fled from the Palestinian territories because of persecution by the Muslim majority. Even if we include the maximum possible total the number comes to a maximum of ca. 7.9 million worldwide, certainly far short of the 12.2 million figure, that is clearly false and over one third over-estimated. You can never believe any Palestinian data, it is all adjusted to fit what they would like to believe.