Making payroll has always been a bit of a fraught experience for Shelley O’Sullivan and her husband at their five-employee construction firm located just north of San Francisco. But a simple mobile app has reduced that anxiety.

“The hassle we were always having with the computer issue is that we do payroll on Thursday and so we have to be home and input it by 3 o’clock to get the checks (out) by the next day,” said O’Sullivan, whose husband started using the iPhone app offered by their payroll service provider, ADP, a month ago. “Now that we have an app he’s out in the field and hits a button and boom, it’s done.”

O’Sullivan said the app is especially handy for their construction business, as they normally spend a lot of time outside the office on sites.

“We don’t have a secretary we can call it in to,” said O’Sullivan, who has been running O’Sullivan Construction with her husband for the past 15 years. “Construction has been very challenging in this economy, so every minute my husband’s out in the field is very important in keeping the business going.”

ADP, which manages the payroll accounts for more than 550,000 clients, is targeting its new app to business owners like the O’Sullivans who have less than 20 employees and don’t have the means to hire extra staff to make sure the checks get issued every two weeks.