John Dumoulin has never really set foot in an office. He works part-time at Chick-fil-A.

But the 17-year-old from northern Virginia is the undisputed king of that bane of office workers everywhere — the spreadsheet. Dumoulin won an international competition on Microsoft Excel proficiency, earning $10,000 in prize money along the way.

Dumoulin learned about the competition after taking an IT class at school in which he earned certifications on various office software products. As it turned out, his score on the Microsoft Excel 16 certification exam was the highest in Virginia, qualifying him for a national competition in Orlando, Florida.

He won, earning a $3,000 prize and an expense-paid trip to the world competition in Anaheim, California, last week.

Dumoulin was a bit taken aback when he saw how seriously the international competitors approached the tournament. No American has won the Excel competition in 16 years, though they have won on other Microsoft Office products including Word and PowerPoint.

"Some of the foreign countries, they've been training for hours and hours and hours on end," he said. "When you first meet the international students, everyone's friendly, but when they find out you're competing against them in the same category, they get this fire in their eyes. They want to win."

Aaron Osmond, general manager of Certiport, the American Fork, Utah-based company that runs the competition, said the Excel competition is more mathematical and analytical than the other categories, and is usually won by countries that place an extra focus and science, technology and math education.

"It's a huge accomplishment," Osmond said of Dumoulin's victory at the world competition, which included a $7,000 prize.

Certiport limits the competition to ages 13 to 22; the company contracts with Microsoft to offer certification testing and educational materials designed to teach the software to high school- and college-age students, something they say is a crucial part of a modern career-tech curriculum.

Osmond said the skills help students land job offers, and they are often far more advanced on the programs than even veteran office workers who routinely work with spreadsheets.