Karl Ebert can credit the Roth IRA for his success. It was 1998, and Ebert thought he might convert some money from a traditional IRA to a Roth. But he couldn't find a calculator to show him if it made financial sense.

So the computer science minor with an MBA in finance built a calculator.

"It worked great. And my goal was to market it and sell it," he said. But he wasn't sure he could pull it off. "Having no contacts and no means of actually marketing that one little calculator, I quickly realized it was something to put on my website that was pretty cool."

About that website: The University of Minnesota grad, who bought a house a mile from campus in the area known as Dinkytown, purchased the url www.dinkytown.net in 1997. He'd hoped to turn it into a community site for the area that made money from local business advertisements. But he couldn't convince stores and restaurants to sign on. "No one was using the Internet in 1998," he said.

He decided to slap up his Roth IRA calculator and a few others he'd programmed, and threw up information about how people could buy them and stick them on their websites. Then one day, "My wife called me ... and asked me who this person was, 'because they just sent you a check.'" He doesn't remember who first licensed his calculators, but they sent him $250. And a business was born.

Each time he created a calculator, he's put it on dinkytown.net, where people could use them for free. "Search engines found them very well," he said.

Clients small and large -- the ones who would pay to put it on their own websites -- did too, without Ebert having to hire a sales guy or advertise.

A calculator for every need

A dozen years later and Ebert has as many as 10,000 clients ranging from individual websites to financial institutions such as Anchor Bank, Thrivent Financial for Lutherans and U.S. Bank. More than a million people visit www.dinkytown.net each month, with spikes in traffic once new year's resolution to shore up finances are put in place. The retirement planner, mortgage qualifier and 1040 tax calculator are perennial favorites. I like the lunch savings calculator myself.

Thrivent has about 80 of Ebert's financial calculators on its website. Scott Wisgerhof, director of advice tools strategy, says the calculators add value for time-strapped consumers who want to do some number-crunching. "These aren't the end-all, these aren't financial planning by any means, but this is a good way for clients to get a directional read on where they're heading on specific issues. We'd still like them to come talk to us to get more in depth," he said.

Today, Ebert has built 471 calculators on topics such as retirement planning, housing finance and debt payoff that are available to the public and dozens of customized projects for financial institutions. He recently finished a series of calculators designed to help investors -- including himself -- decide whether to convert pretax retirement dollars to a Roth IRA. Now he's working on one that figures out how looming tax changes in 2010 will affect an individual's tax picture.

In order to create the calculators in the first place and then keep up with the ever-changing tax code, Ebert is a frequent visitor to IRS.gov and voracious reader of financial publications.

But he doesn't mind. He's a bit of a personal finance geek. In sixth grade, "I made a compounding interest calculator on my computer -- a TI-99/4A" and confronted his dad about how $1,000 invested on the day he was born could have grown in 11 years.

Earning vs. saving

So what's his money style today? "I don't waste money. I don't save money. I earn money." Ebert explains: "It's easier to earn more money than to save it. If I can earn $100, should I earn the $100 or make the same effort to save $10? I'll choose earning the $100 ... I am saving [money], but the reason I'm saving it is not that I'm focused on limiting my spending," he said.

Still, while he's not a penny pincher, he admits he's naturally "pretty cheap." He works in the basement of the house he's owned for 16 years, even though three kids now rule the roost. He also drives a 1995 Explorer he bought from his sister-in-law.

If he had one piece of advice to share (besides using his calculators) it's this against-the-grain wisdom: "Acquisition costs of things is where your money can really be sucked away fast. You could buy an awful lot of lattes for the financing of a new car. And you could buy a lot of new cars for the cost of financing that new house. So if you look at those top-level items first, then the day-to-day stuff doesn't matter."

Kara McGuire • 612-673-7293 or kmcguire@startribune.com