Donald Trump will write his presidential campaign a check for $10 million Friday, he said in an interview scheduled to air later in the day.

Fox News' Brett Baier sat down with Trump for an interview at Trump Tower in New York City. Baier wrote on Instagram that Trump confirmed he'll donate some of his own money to his campaign, a practice he's done before. But the amount promised leaves him well short of the $100 million he pledged to donate to his Republican bid for the White House.

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CNN reports that Trump gave his campaign $31,000 in the first 19 days of October. That left his total self-investment at $56.1 million.

Friday's $10 million addition to that figure would still leave him just under $34 million short of his pledge.

The Washington Post provided amounts that other self-funding political candidates have given to their campaigns. On the list is Democrat Hillary Clinton, who the numbers show was worth $30 million during the time of the 2008 presidential campaign. She donated $13.2 million to herself.

Mitt Romney spent $44.7 million of his $250 million fortune on his 2008 presidential campaign. Meg Whitman, who in 2010 was worth $1.3 billion, spend a reported $144.2 million of her own cash on her failed bid to become California's governor six years ago.

Trump's campaign raised $29 million through the first 19 days of October, leaving him with $16 million in cash on hand. Clinton took in more than $57 million and had $62 million available, reports CNN.

The Washington Post's Chris Cillizza surmises that with a week and a half before election day, more donations to Trump's campaign might not do much to improve his chances of winning. That money is good for TV ads and hiring staff.

However, Republican strategist Jim Bognet told CNN there are plenty of ways for Trump's campaign to spend any additional money the real estate mogul gives it.

"If you don't care about price and efficiency, you could definitely spend tens of millions of incremental dollars in a presidential race in the last 10 days of campaign," Bognet said. "In crowded swing state airwaves, it's hard to get incremental space on broadcast TV at this time in true battlegrounds."

Bognet added that in the closing days of a campaign, TV air time becomes "super expensive."