Not your father’s office space.

Office space planning for the millennial generation.

In today’s office environment, bigger isn’t always better. Gone are the days when each employee was treated to his or her own private office, racing up the corporate ladder to larger, more coveted offices.

According to a report by Property Portfolio Research, the size of the average American office has decreased by 21 percent over the past decade. And real estate data provider, CoreNet Global, estimates that American offices now average 151 square feet per worker. Put together, it provides fertile ground for workspaces that are more collaborative, more open, occupies fewer square feet and, yes, cost less. So just how much office space does your small business need?

The rule of thumb for office space planning is this: Think smart. Plan well. If you’re moving into a new office, reorganizing your current space, downsizing or “smart-sizing,” keep these three tips in mind when determining how much space you need.

1. Make a List. Check it Twice.

Any good planning project begins with a list. If you’re planning office space, start early by defining your space. with a list of employees and their office space requirements. Maybe the boss needs an office, but Becky, George and Lisa need cubicles in a shared, open area. If you need a conference room, reception area, break room or storage space, you’ll want to add that in, too.

2. Plan for Growth

Why spend time and money planning and outfitting your office space, only to outgrow it and do it all over again? If you plan for growth now (think three to five years out), you can avoid growing pains later. A good rule of thumb is to carve out 125 to 225 square feet of office space per employee. But if you plan to grow your company, don’t forget to add in those future employees.

3. Get Technical

When planning your office space, don’t forget to include your technology needs, such as access to and wiring and cabling for computers, servers, fax machines, telephones, copiers and video conferencing equipment. It even includes break room appliances, such as a refrigerator and coffee machine. Think about where these items will live so your contractor can plan for them before you move in.

Search the internet for companies that specialize in it or property management companies that offer space-planning services. You’ll get an expert assessment of your current office space and future needs, including office workflow, space usage, amenities, energy efficiency, leasing costs and technology requirements. You could even save as much as 20% on your current occupancy costs and eliminate office space that doesn’t fit your needs.