The presidential candidates and their allies plan to spend more than half a billion dollars on television and radio advertising over the final seven weeks of the campaign.

Groups backing Vice President Kamala Harris have reserved $332 million worth of airtime for television and radio ads — 63 percent of the total — while just about $194 million will come from groups backing former President Donald J. Trump, according to data supplied by AdImpact, an advertising tracking firm.

The ad wars are the consequence of the fund-raising wars: Democrats have significantly out-raised Republicans in the months after Ms. Harris succeeded President Biden as the head of the Democratic ticket, and Ms. Harris has more money to spend on paid media.

Ms. Harris’s campaign has portrayed her as the underdog and often points to the existence of several outside Republican groups to argue that Democratic donors should not be complacent. But the biggest spender by far in the campaign is Future Forward, the main super PAC blessed by the Harris campaign, which is scheduled to spend $186 million on television and radio over the final 49 days.

The Harris campaign itself is spending more than the Trump campaign in the remaining weeks of the election. Ms. Harris is set to air about $109 million in advertisements, while Mr. Trump will air about $98 million worth.

The state where the candidates and their allies plan to spend the most money on advertising is Pennsylvania: $133 million in all. Democrats have about a $21 million advantage in the state.