Every three months, Katerina Newell packed away another round of clothing outgrown by her young children.

And every three months, she felt bad about it.

“It was like, well, I bought this dress for my daughter, she wore it a few times and now it’ll never see the light of day again,” said Newell, a former attorney. “I just kept thinking there had to be a better way.”

Last summer, she came up with a solution: Wearhop, an online rental service for children’s’ clothing. The company, which Newell runs out of her Falls Church home, has roughly 1,000 items for rent. Parents pay a varying monthly fee for each piece, depending on whether it is new or used.

“The goal was to help parents save money,” she said. “And instead of spending time reselling or donating old clothing, they can just send it back.”

A $75 Ralph Lauren sweatshirt, for example, costs $18 to rent used and $30 to rent new for the first month. (Subsequent months cost less.) The $5 shipping fee also includes a pre-paid envelope that parents can use to return the clothing once they’re done.

Newell said she invested $60,000 of her own money to get started.

The bulk of that money — about $50,000 — went toward buying clothing from brands such as Baby Gap, Janie & Jack and Crewcuts. The rest went toward the development of the Web site.

Newell would not disclose sales figures, but her business is very much the start-up. She said that 2013 revenue totaled at least $10,000. She expects sales to triple in 2014.

Sites such as Netflix, Rent the Runway, and Bag Borrow or Steal, which offers rentals on designer handbags, have popularized the idea of online rental services in recent years. A similar children’s site based in Baltimore, Borrow Mini Couture, offers luxury pieces by the likes of Dior and Versace.

At Wearhop, parents have the option to extend monthly rentals (up to six months at a time) or purchase items they like, Newell said. If clothing is damaged or torn, they are asked to pay full price.

“The idea is to be flexible,” she said. “Sometimes kids have unpredictable growth spurts. Sometimes they get messy.”

Nicola Perceval, who lives in Bethesda, ordered a party dress and cardigan for her 4-year-old this holiday season.

“If it weren’t for this site, I probably would have either gone to the consignment store or bought a new dress,” Perceval said.