Reg Groombridge took a sharp intake of breath as he looked over his firm’s latest accounts.

“Our turnover is frightening,” said the co-founder and director of WhosOff.com, whose nine staff are set to bring in revenues of £1.2 million this financial year.

Last month, the company recorded the 100,000th user of its web-based leave planner, which serves 2,500 companies in more than 65 countries.

“You hope for this type of growth,” said Mr Groombridge, who estimates his company has saved more than 1,500 trees and processed more than three million leave requests since it launched in 2006.

Its system allows staff to ask for holiday online or via a mobile app which notifies the appropriate manager straight away. Bosses can respond to requests in minutes and updates are made using live online calendars.

“But looking after staff leave can become a very time wasting ‘spreadsheet hell’ or ‘wall planner pain’. The answer is online...” - Reg Groombridge, WhosOff.com

It all sounds very simple but its time-saving ability has caught the attention of some big players keen to take advantage of the 90 minutes of manpower which WhosOff.com estimates it saves dealing with each holiday request.

Clients include parts of the NHS, large TV networks, private healthcare giants and large online travel agents.

“Some huge companies are only just coming to the delivered services market,” said Mr Groombridge, a former ferry worker at the Port of Dover. “They are only just realising this is the way to do things.

“Knowing who’s off today, who’s off tomorrow, next week or how the summer period is looking is all relevant to planning and running any successful business.

“But looking after staff leave can become a very time wasting ‘spreadsheet hell’ or ‘wall planner pain’. The answer is online.”

The business has changed a great deal since it started off on the kitchen table of Mr Groombridge’s home in Temple Ewell, near Dover.

It began as X:drive Computing, a software company which computerises paperwork for the haulage industry.

Originally the online holiday booking service was offered for free to clients but when Mr Groombridge and his business partner Phillip Cross saw the opportunity it presented – and realised the man-hours it was using – they made the big decision to turn it into a paid facility.

“We are delivering a service to the rest of the world from Kent...” - Reg Groombridge, WhosOff.com

“We were really shocked at the outcome. It gave some businesses the confidence to use it because they didn’t trust a free service and more than 60% of our customers stayed with it, even when we change it from free to paid.

“That was a big message to us that we were on to something big and we have built it up over the years.”

Today the business is a subsidiary of X:drive and has moved offices several times, taking a “cupboard” in the University of Kent at one point and working from a house in Canterbury at another.

Last year, the company bought an entire floor of the Beer Cart Building, the former council offices in the centre of the city.

“That was only possible because of the number of users we have. It has enabled us to hire staff and is a signal we aren’t looking to sell up tomorrow. We are investing in Kent.”

The firm is now working on a new project, WhosOffice, applying their technology to companies which run shift patterns, which has already attracted some paying customers.

The business operates using servers at Kent Science Park in Sittingbourne.

Mr Groombridge added: “We are delivering a service to the rest of the world from Kent.”