Keeping track of your work is getting simpler to do on a smartphone, and a Minnesota start-up is taking new steps to make that happen.

When I Work, a St. Paul company with a fast-growing employee scheduling and time clock business, has raised another $5 million in venture capital and will acquire a smaller Canadian competitor, the firm said Monday.

By offering mobile-ready software that's easy to use in a field littered with unwieldy competitors, the company is carving out a huge chunk of business and revenue is growing at double-digit rates each month, Chief Executive Chad Halvorson said in an interview.

Formerly known as ThisClicks, the company already serves more than 10,000 businesses worldwide in 35,000 locations, including Tesla, Walgreens, Ace, Uber, Dunn Brothers, Ben & Jerry's and some divisions of Medtronic. That's up from 3,000 businesses just 18 months ago.

"It's really, really hard to build software in the workforce management space that isn't a nightmare to use and train," Halvorson said. "At the end of the day, it is just simplicity. This isn't just a product that one person uses at a business, it is something that the entire organization has to use and understand."

When I Work will acquire ShiftHub, a Toronto-based workforce management firm with a few hundred customers that Halvorson said offers one of the better solutions for businesses looking to modernize their timecard and scheduling software. Terms of the deal were not disclosed, but Halvorson said most of the new $5 million round of funding won't be needed for the deal, and his company will be on the lookout for other acquisition targets.

Wait for market to catch up

Halvorson, who grew up in Thief River Falls, Minn., the son of a railroad worker and a Digi-Key invoicer, first registered the WhenIWork.com domain in 1998 as a teenager, but shelved the idea in 2001 after concluding the market wasn't ready. He worked for about a decade in consulting, but when the iPhone was released he revived his old idea and relaunched the business in 2010 with a focus on the mobile app.

The company got to $1 million in annual revenue before even looking for venture capital funding.

The firm raised $4 million in financing in 2014 from three investors: E.ventures, Greycroft Partners and Arthur Ventures. Its new round of $5 million comes from the same three.

Arthur Ventures is also a key investor in LeadPages, another of the Twin Cities' hottest start-ups. E.ventures was one of the investors in Angie's List, which went public in 2011.

Aaron Kardell, the founder and CEO of HomeSpotter, another fast-growing Twin Cities start-up, said When I Work is widely considered one of a handful of start-ups in Minnesota to watch. Halvorson is held in high regard for fusing marketing, design and software development expertise, and while his company is not as far along as Sport Ngin or LeadPages, its growth rate has commanded the respect of the local start-up community.

"They've tapped into a big need with just their core product," Kardell said.

Since the first round of funding, When I Work has grown from 12 employees to 60 and expects to double again over the next 12 months. Halvorson wouldn't reveal annual revenue, but said sales grew more than 300 percent in 2014 and will grow by the same amount in 2015.

When I Work's services cost businesses from $1 to $2 per month per employee, and often spread by word of mouth when employees switch jobs and show the app to their new manager or owner.

"We're trying to connect every hourly worker on the planet to When I Work," Halvorson said.