A US teenager who has made more than $480,000 from her babysitting business has hired a chief executive to handle day-to-day business matters while she's at high school.

Noa Mintz, 15, founded her child care agency Nannies by Noa three years ago and now has 190 clients, the New York Post reports.

The teen entrepreneur charges a 15 percent agency fee of a nanny's initial salary of around $64,000 to $100,000 and a flat fee of $5 an hour for babysitting services.

The agency has 25 full-time nannies and 50 babysitters who reportedly work an average of 15 hours per week.

Ms Mintz started her business at 12 when she became fed up with her own babysitters.

"For what you're paying, your kids should be more stimulated," she told the media outlet.

"At 7, I would tell my mum, 'You need to get more bang for your buck.' It would drive me insane!"

She worked with her investment banker father who went guarantor for her business and recently hired Allison Johnson as the company's chief executive. Ms Johnson, 26, is a trained social worker who had first applied to Nannies by Noa for a nanny position.

"It was a little bit of a challenge at first,” she told the media outlet, referring to taking orders from a teenager and negotiating her salary.

"She was 14! [But] I’m a feminist, and I really support women who do things for themselves and get their visions out there.