Did Joe Biden Receive Millions More Votes Than There Were Eligible Voters?

A viral article from Gateway Pundit claims that “simple math” proves President-elect Joe Biden received 13 million more votes “Than There Were Eligible Voters Who Voted in 2020 Election.”
The article is based on a viral tweet, which stated: “With 212Million registered voters and 66.2% voting,140.344 M voted. Now if Trump got 74 M, that leaves only 66.344 M for Biden.”
The tweet author’s math is off slightly based on the information he provides: Adding up the number of registered voters per state as listed on the website cited results in a figure of 213,799,467 registered voters. But a bigger error is made in the tweet: The Washington Postarticle from which the 66.2 percent figure is pulled refers to the voter turnout among the eligible voting population, not registered voters, as stated in the tweet and the subsequent Gateway Pundit article. Not all eligible voters end up registering to vote, with an estimate from Pew Research based on census data in 2017 suggesting that 21.4 percent of eligible voters were not registered to vote in 2014.