Speaking after the interview, Labour leader Jeremy Corbyn said he was "not embarrassed in the slightest".
In a stumbling explanation of how Labour would fund the 10,000 extra police officers, Diane Abbott put the bill at £300,000, before suggesting it would cost £80 million per year - meaning the officers would earn £8,000 per year.
The MP for Hackney North and Stoke Newington assessment of how many new officers would be recruited in one year ranged from 25,000 to 250,000 - meaning at most there could be an extra one million police officers over the four year period Labour has said the officers would be taken on in.
Pausing and stumbling through her interview with host Nick Ferrari, Ms Abbott said: "Well, if we recruit the 10,000 police men and women over a four-year period, we believe it will be about £300,000."
Ferrari replied: "£300,000 for 10,000 police officers? How much are you paying them?"
Ms Abbott replied: "No, I mean, sorry, they will cost, it will cost about, about £80 million."
"About £80 million? How do you get to that figure?" he said.
Ms Abbott answered: "We get to that figure because we anticipate recruiting 25,000 extra police officers a year at least over a period of four years.
"And we are looking at both what average police wages are generally but also specifically police wages in London."
Mr Corbyn spoke after the interview to defend the shadow home secretary.
"She corrected the figure and that's the figure and it will be paid for by not going ahead with the cuts in capital gains tax," Mr Corbyn told Sky News.
Asked if it was embarrassing that Ms Abbott got the figures wrong, he said: "Not at all. We have corrected the figure and it will be absolutely clear now, today and in the manifesto."
Ms Abbott also told ITV News after the interview that she "misspoke" and insisted she is "completely on top of her brief", emphasising the fact it was the "sixth interview out of seven".
She confirmed £300 million was the figure she was supposed to say.
Labour has said the extra police officers would be funded by reversing Tory cuts to Capital Gains Tax (CGT).
CGT is a tax on the profit when an asset which has increased in value is sold.
In last year's Budget, the Government announced plans to cut the higher rate of CGT from 28% to 20% and the basic rate from 18% to 10%.
Ms Abbott's blunder was quickly seized on by the Conservatives, who claimed it showed that Labour's sums "don't add up".
Home Secretary Amber Rudd said: "Diane Abbott has laid bare the chaos that Britain would face if Jeremy Corbyn is voted into Downing Street.
"One of Corbyn's closest allies has clearly shown that Labour's sums don't add up, they would weaken our defences, and their nonsensical promises aren't worth the paper they are printed on.
"Jeremy Corbyn and his coalition of chaos pose a grave risk to our economy and our national security. We would all pay the price if he ends up in Number 10 propped up by the Lib Dems, Greens and SNP.
"Only Theresa May and the Conservatives can be trusted to deliver the strong and stable leadership for Brexit and beyond."