Over the past 30 years, multisite churches have been the most popular strategy for church growth. Ed Stetzer tells us that 85 percent of multisite churches are growing, compared with less than half of more traditional models. And the rate of growth is a healthy 14 percent among those churches.

Who knows how long this trend will last? But it’s clear that a multisite model is one viable option for growing churches. Which brings up the math question I want to tackle today: When do I know it’s time to add another campus?

Adding a campus is a difficult move. The learning curve is steep, and the cost is dramatically higher. Make sure you’ve exhausted all other options, including adding additional service times. However, the reward can be incredible if you pull it off right and the Lord is in it.

So, what should you measure, evaluate and calculate when thinking about adding another campus? Let me give you two overarching indicators that can point you in the right direction.

When Your Attendance Outgrows Your Current Building

This is the most obvious one. When you hear people complaining about having trouble finding a parking spot, when the lines for child check-in are out the door, and it’s difficult to find an open seat, you know you’re feeling the effects of growing pains. As you see your building fill up, the next logical step may just be another campus.

Here are some questions to ask when you’re counting the cost of adding another campus. Remember, each church will be unique, and each new campus will be a little different than the last. The size of the new building, parking capacity and economic factors play a role when you launch. But, as a general rule, these questions are great guiding principles.

How many people will you need to make up the core group at the new site? Determine a critical mass for your new campus. One rule of thumb is 25 percent of the sending church’s attendance. If you’re experiencing growing pains at your current location, ask yourself how it would feel to operate at 75 percent of your current attendance. That may give you a clear picture of when it’s time to take the plunge.

First, find out who will make up the core group. The obvious answer will be those who live near the location of the new campus. But make sure you ask for volunteers from your entire congregation. You may have some members with a pioneering spirit, ready to increase their drive time on Sunday mornings to help advance the Kingdom.

Before you launch, consider incubating that core group several weeks ahead of time. If you have room at your current location, have them meet separately on Sunday mornings as a dry run. Also, use that time to identify key volunteer leaders and position everyone into a place of service at the new campus. That way, you’ll hit the ground running.

How many new staff members will you need to minister at another campus? With any new campus comes new staff to support it. Your current staff is focused on the present location. Stretching them beyond capacity to launch a new site while maintaining their present work is counterproductive. Bringing the right people on board at the right time sets you up for success.

It’s clear that a multisite model is one viable option for growing churches.

The first staff member you’ll need is a campus pastor. Please don’t consider making this a volunteer position. A full-time pastor with a singular focus on launching and growing this new campus will give you the best results. The next two most-needed positions are worship pastor and children’s pastor, perhaps followed closely by a youth pastor, depending on the average age of your core group.

So, the leanest staff you should launch with is a three-member team. Is your budget ready to handle those additions? And if you think you can shift someone from the main campus to the new campus, you will still need to backfill their original positions.

How much margin do you need in your current budget to be ready for this kind of growth? It’s not just additional staff that will be a drain on your budget. You have to consider other costs, such as facility rental or mortgage, equipment and fixtures, along with any renovations for a purchased building, advertising, additional printing costs and adjustments for unforeseeable expenses.

According to Ed Stetzer, the median cost for a new campus is $145,000. You should make sure you have that on hand before making the jump.

One other thing to consider is whether your next campus will be financially independent from day one. If your core group is large enough and committed enough, this won’t be a problem. But in many situations, the more established campuses shoulder the load of adding a new site for at least the first year. Factor that into any budgeting you’re doing.

When Your Vision Outgrows Your Current Location

As your church grows, so does your vision. What you thought was only a dream in the past may start coming into focus when you consider another campus location. It may be an outreach to an area of town further away from your present location. Or it may be a whole new demographic that your people have a heart for. Adding another campus will position your church to chase that vision.

Start by looking at the people who are already coming to your church. Who drives the farthest? Where are the largest groupings? Where are they doing life together already? Don’t make the mistake of launching another campus that is too close to your current one. Use this as a way to leverage new areas of ministry for your church.

There is no perfect time to launch another campus. If you live by the motto that “failure is not an option,” you may not get very far. You can never have every base covered, and there’s always something that can go wrong. But the only real failure is the “failure to launch.”

When God has given you the green light, your board is comfortable with the finances, your staff is on board with the changes, and your congregation is excited, be bold and take that step!

See also “When It’s Time to Add, Part 1: Launching a Second Service” and “When It’s Time to Add, Part 2: Recognizing the Right Time to Hire a New Staff Member.”