Belgians work on 13.92 pay cycles a year. Nigerian taxes must be paid in person. Italian law says fired employees may be eligible for severance equaling up to two years’ salary. How do multinational companies keep it all straight? Many are turning to Michele Honomichl, whose Chicago-based firm, Celergo, ensures that far-flung employees are paid the right amounts — the right way.

Honomichl (pronounced HAN-ah-michael) is something of a pioneer in the burgeoning field of international payroll. While she was working in human resources at Ford Motor Co. F , Honomichl was part of a team that created an expatriate management system to help the carmaker manage employees in 35 countries. After earning an MBA from Indiana University, Honomichl, who never lost interest in global employment issues, in 1999 founded a company called GPSLink, which automated the mounds of paperwork that corporations process for international workers.

Over time, more GPSLink customers started asking for help with payroll. “There was really a market there,” Honomichl says. So in 2004 she and Bert Brown, a GPSLink partner, wrote a new business plan and relaunched the company as Celergo. (The name comes from two Latin words and loosely translates as “swift payment.”) Its first client was a telecom company that needed help with payroll in Dubai, a relatively straightforward assignment, Honomichl recalls, be cause there are no salary tax deductions in the country.

Celergo’s edge is that its systems and local country partners keep track of such minute details — e.g., the countries that don’t deduct taxes (much of the Middle East) and the ones where time off is paid at a higher rate than your regular salary (France) — so its clients don’t have to. “Celergo is a pioneer,” says Andrew Lindner, managing partner at Frontier Capital, which invested $15 million in the company in 2011. Payroll rivals such as ADP ADP and Ceridian also handle business in individual countries. But Lindner says Honomichl’s company breaks ground by offering corporations a one-stop solution for paying employees across multiple nations. Celergo, which reported sales of $19 million last year, processes payroll for 150 clients in 110 countries. It has offices in London, Singapore, and Budapest, and its employees speak 36 languages.

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Honomichl, a Chicago native, has worked in many countries, including Venezuela, Brazil, and Mexico, and can rattle off exchange rates and fun facts about cultural differences like a foreign correspondent or a diplomat. She says she believes her technology isn’t just helping corporations — it is enhancing the quality of life for tens of thousands of employees, many working in emerging markets. “How do you standardize the world?” she asks. “You pay people accurately, on time, every time — regardless of culture, country, or crisis.” And that’s the kind of payoff that can’t be measured in euros, dollars, or dirhams.

This story is from the June 10, 2013 issue of Fortune.