711,000 according to the General Progress Report and Supplementary Report of the United Nations Conciliation Commission for Palestine, Covering the Period from 11 December 1949 to 23 October 1950, published by the United Nations Conciliation Commission, October 23, 1950. (U.N. General Assembly Official Records, 5th Session, Supplement No. 18, Document A/1367/Rev. 1) [note 2]
472,000 in October, 1948, according to the Progress Report of the Acting United Nations Mediator on Palestine published by Acting UN Mediator Ralph Bunche, October 18, 1948. (UN General Assembly Official Records, 3rd Session Supplement No. 11A, Document A/689) [note 3]
Estimates of total number of people who registered as refugees
800,000 – 900,000 according to the Historical Survey of Efforts of the United Nations Conciliation Commission for Palestine to Secure the Implementation of Paragraph 11 of General Assembly Resolution 194 (III) published by the United Nations Conciliation Commission, October 2, 1961.  (A/AC.25/W.81/Rev.2)
875,998 refugees in June 1951, according to the Report of the Director of the United Nations Relief and Works Agency for Palestine Refugees in the Near East published by the United Nations Relief and Works Agency, September 28, 1951. (U.N. General Assembly Official Records, 6th Session, Supplement No. 16, Document A/1905) [note 4]
957,000 refugees in 1950 according to the Report of the Director of the United Nations Relief and Works Agency for Palestine Refugees in the Near East published by the United Nations Relief and Works Agency, September 28, 1951. (U.N. General Assembly Official Records, 6th Session, Supplement No. 16, Document A/1905) [note 6]
400,000 "Israeli government estimate" according to Elia Zureik 
539,000 According to Dr. Walter Pinner, Dr.Econ, Halle-Wittenberg University, in his book How many Arab refugees: a critical study of UNRWA's Statistics and Reports Page 61 "The number of genuine refugees in 1948 was 539,000."
600,000 According to Joseph B. SchechtmanThe Arab Refugee Problem 1952 Philosophical Library. Page 16 "The number who fled could not have exceeded 600,000."
600,000 – 700,000 According to Nicole Brackman on www.aijac.org.au 
630,000 According to Yoram Ettinger on www.acpr.org.il 
700,000 "It is impossible to arrive at a definite persuasive estimate. My predeliction would be to opt for the loose contemporary British formula, that of 'between 600,000 and 760,000' refugees; but, if pressed, 700,000 is probably a fair estimate" – Benny Morris, The Birth of the Palestinian Refugee Problem Revisited, p603-4.
720,000 According to www.jafi.org citing "Irving Howe and Carl Gershman (eds.), Israel, the Arabs and the Middle East (New York: Bantam, 1972), p. 168." 
750,000 – 800,000 "Private Palestinian sources" according to Elia Zureik 
800,000- According to Amira Howeidy on Al-Ahram Weekly online. 
^This estimate by the UN Conciliation Commission has been repeated in a number of other UN documents , . The number was calculated by estimating the number of non-Jews living within the borders of Israel at the end of 1947 and subtracting the number of remaining non-Jews living within the borders of Israel after the war. It does not include an estimated 25,000 border-line refugees – refugees who lost their livelihood because their village land was located in Israeli-occupied territory, while the village house remained in Arab territory. The figure was later revised down by the UN Concilation Commission to 711,000. 
^The Committee believed the estimate to be "as accurate as circumstances permit", and attributed the higher number on relief to, among other things, "duplication of ration cards, addition of persons who have been displaced from area other than Israel-held areas and of persons who, although not displaced, are destitute."
^ abFigure refers only to people registered as refugees.
^Figure inflated because "all births are eagerly announced, the deaths wherever possible are passed over in silence, and as the birthrate is high in any case, a net addition of 30,000 names a year".  The figure includes descendants of the Palestinian refugees born after the Palestinian exodus up to June 1951.
^Figure does not match official UNRWA estimates submitted to the UN.
^Figure later revised down to 876,000 by UNRWA after "many false and duplicate registrations weeded out." 
^Figure calculated by using the official village statistics of 1944/1945 and upgraded to 1948/1949 by taking a net natural increase of 3.8% for four years. The number of non-Jews remaining in Israel was then deducted from the total count.
1 The UNRWA definition of a "Palestinian refugee" is a person "whose normal place of residence was Palestine between June 1946 and May 1948, who lost both their homes and means of livelihood as a result of the 1948 Arab-Israeli conflict ... UNRWA's definition of a refugee also covers the descendants of persons who became refugees in 1948."