President Donald Trump, who claims to be “like, really smart,” speaks at the level of a fourth-grader, a new analysis has found.

The website, Factbase, that worked as a database of Trump's interviews, speeches, and tweets, analyzed the first 30,000 words uttered by the president while in office and ranked his speech on the Flesch-Kincaid grade level scale.

The speech was also put through more than two dozen other tests that analyzed English-language difficulty levels. Trump's interviews, speeches, and tweets were run through different lexicological tests, studying for vocabulary, comprehension levels, and complexity. “Off-script” remarks and not those written by the speechwriters of all the previous presidents were used to compare and contrast their speaking skills. Social media posts were excluded from the data.

Following the tests, Trump’s speech level was found to be that of a mid-fourth grader. Further analysis of speech patterns and comparison to the last 15 presidents revealed that Trump was the worst since former president Harry Truman, who spoke at the almost sixth-grade level, being around 1.3-grade levels higher than Trump.

The Flesch-Kincaid formula, used to assess the grade-level of the reader, was actually developed for the military in the 1970s in order to make sure that that training material provided to the personnel were appropriate and could be understood. It is also used as a measurement in drafted legislation to ensure that documents like insurance policies can be understood.

"By every metric and methodology tested, Donald Trump’s vocabulary and grammatical structure is significantly more simple, and less diverse, than any President since Herbert Hoover, when measuring “off-script” words, that is, words far less likely to have been written in advance for the speaker,” wrote Factba.se CEO Bill Frischling in the report.

The top three on the grade level list were Herbert Hoover (11.3), Jimmy Carter (10.7) and Barack Obama (9.7).

Trump used fewer "unique words" than any president as well as the fewest average syllables which Obama was apparently most fluent in using.

The results of the analysis seemed to complement findings obtained in March 2016 from a team at Carnegie Mellon University that analyzed the speeches of many 2016 presidential candidates with the previous president and equated Trump's grammar skills to those of a 6th grader. In this particular study, the former president was found to have the best grammar of all— at the 11th-grade level.

The analysis came following Trump’s tweet Saturday in which he reminded everyone that he was elected to the presidency “on my first try.”

 “I think that would qualify as not smart, but genius....and a very stable genius at that!” he wrote. In another tweet, he wrote: “…throughout my life, my two greatest assets have been mental stability and being, like, really smart."

In comments at Camp David later, he explained his tweet and said that he was “a very excellent student.”

“I had a situation where I was a very excellent student, came out, made billions and billions of dollars, became one of the top business people, went to television and for 10 years was a tremendous success, which you've probably heard."

Questions about trump’s mental stability were raised in light of the release of journalist Michael Wolff’s explosive tell-all book “Fire and Fury: Inside the Trump White House,” in which certain revelations suggested that the president was not mentally fit for office.