Looking Up Presidential Information Online
I spent way too many years helping people find basic historical facts on the internet, and one of the most common questions I see comes up in forums, help threads, and student message boards. People want to know who held a particular office, and they usually type it out with whatever phrasing comes to mind first. The search results can be messy. The actual answer is straightforward once you know where to look and how to verify it. The 33rd President of the United States was Harry S. Truman. He took office on April 12, 1945, after Franklin D. Roosevelt died in office. Truman served out the remainder of FDR's fourth term and then won the 1948 election in what is still considered one of the biggest upsets in American political history. He left office on January 20, 1953, having served just under eight years total.
Who Was The 33th President
That exact phrasing shows up a lot in student homework help posts and casual Google searches. It is not technically correct English — the ordinal should be "33rd" — but search engines understand it anyway. Harry S. Truman is the answer either way. The middle initial S does not stand for anything. It was accepted as a standalone initial, and he insisted on keeping it that way throughout his life. People constantly try to decode it as a tribute to two different uncles, but Truman himself said it was just what his family used and he had no interest in assigning meaning to it. One thing most quick-reference sources get wrong or leave out is the succession detail. Truman was not elected to the presidency initially. He was FDR's running mate in 1944, replacing Henry Wallace, and became president by virtue of the vice presidential line of succession. That distinction matters if you are writing a paper or preparing for a trivia competition, because the question "who was the 33rd president" can sometimes trip people up into thinking Truman won the office outright. He did not. He inherited it, and then he won it on his own merits two years later in 1948. I once spent an afternoon untangling a debate on a history forum where someone was insisting that Truman was the 32nd president because Grover Cleveland counts as both the 22nd and 24th president, which shifts the numbering. That is a real edge case that most people do not account for. Cleveland is the only president with non-consecutive terms, and his dual numbering throws off anyone counting forward from Washington. If you start from 1 and count each person once, Truman is the 33rd individual to hold the office. If you count administrative terms the way the official White House historian does, the numbering stays consistent and Truman remains the 33rd. Both approaches converge on the same person. The confusion only arises when someone mixes the counting methods mid-argument.
For anyone trying to verify this kind of information quickly, the official White House history website, whitehouse.gov/history/presidents/, is the most reliable single source. It lists every president in order with full dates, party affiliation, and succession notes. The National Archives also maintains a clean presidential timeline at archives.gov. Those two sites should be your default references before you trust any random blog or YouTube comment section. I have seen too many people cite wiki pages that had recent vandalism or outdated info, and it took hours to trace back where the incorrect number came from. The deeper issue with looking up presidential facts online is that most people stop at the first result. A quick Google search will give you the answer in about three seconds, but the answer might be wrong if the top result is a quiz site, a fan page, or a low-quality content farm. I recommend opening the White House history page directly and confirming the number yourself. It takes ten seconds and eliminates any doubt about whether a particular source is reliable. That habit has saved me more than once when someone sent me a screenshot of an incorrect fact they found online and expected me to work from their version instead of the primary record. Truman's presidency is also worth noting for the breadth of what happened in a relatively short time. The end of World War II, the atomic bombings, the Truman Doctrine, the Marshall Plan, the Berlin Airlift, the creation of NATO, and the Korean War all fall within his eight years in office. That is a lot of major historical events compressed into one administration, and it is why he is consistently ranked in the upper middle tier of American presidents despite being one of the most unpopular presidents at the time he left office. History has been much kinder to him than his contemporaries were.
Get the Full Details

If you need the answer fast, it is Harry S. Truman, 33rd president, served from April 12, 1945 to January 20, 1953, Democrat, from Missouri. If you need to cite it properly, use the White House history page or the National Archives. That covers the basics without any unnecessary detours.