Staffing and Scheduling: How Many Agents Do You Need?

Staffing is one of the hardest parts of running a contact center. Schedule too few agents and customers wait, give up, and call back angrier. Schedule too many and you pay people to sit idle. The goal is to have the right number of people at the right times, and it’s more science than guesswork.

This guide walks through the basics, from forecasting demand to building a schedule.

Step 1: Forecast how many contacts you’ll get

Everything starts with a forecast: how many calls, chats, and emails will arrive, and when.

Use your history. Pull contact volumes for the past several months, broken into 30-minute or hourly blocks. Look for patterns:

• Time of day: many centers are busiest mid-morning and right after lunch.
• Day of week: Mondays are often the busiest day.
• Time of month: billing dates, paydays, and statement cycles cause spikes.
• Seasons and holidays: retail peaks before holidays, tax services in spring, and so on.

Account for known events. A marketing campaign, product launch, price change, or system outage can drive extra contacts. Ask other departments to warn you about them ahead of time.

No history yet? Start with your best estimate, track actual volumes closely for the first few weeks, and adjust.

Step 2: Know how long contacts take

You also need your average handle time (AHT): talk time plus hold time plus the follow-up work after each contact. If calls average 4 minutes of talking, 1 minute on hold, and 1 minute of notes, your AHT is 6 minutes.

Handle time often varies by contact type and time of day, so use the most specific numbers you have.

Step 3: Choose your service goal

Decide how quickly you want to answer. The most common target is a service level, such as 80% of calls answered within 20 seconds. Chats often use similar targets, while emails are usually measured in hours, such as “answered within 24 hours.”

Your goal should reflect what your customers expect and what you can afford. Faster answers require more staff.

Step 4: Calculate how many agents you need

Here’s where many new managers go wrong. Let’s work through an example.

Example: 100 calls arrive in an hour, each taking 6 minutes on average.

• Raw workload: 100 calls × 6 minutes = 600 minutes, or 10 hours of work in one hour.
• So you need 10 agents, right? No. With exactly 10 agents, every agent would need to be busy every second, and calls don’t arrive evenly. Queues would grow out of control.

Contact centers use a formula called Erlang C to account for the random way calls arrive. For this example, it shows:

Agents on the phones	Calls answered within 20 seconds	Average wait
12	About 60%	About 81 seconds
13	About 76%	About 34 seconds
14	About 86%	About 16 seconds
15	About 92%	About 7 seconds

To meet a goal of 80% within 20 seconds, you need 14 agents on the phones, not 10. Notice how much difference one agent makes: going from 12 to 13 agents cuts the average wait by more than half.

You don’t need to do this math by hand. Free online Erlang C calculators and most workforce management software do it for you. Just enter your call volume, handle time, and service goal.

Step 5: Add shrinkage

Those 14 agents need to be on the phones, available to take calls. But in any shift, agents also spend time on:

• Breaks and lunches
• Training and coaching
• Team meetings
• Absences, sick days, and vacation
• System problems and other off-phone work

This lost time is called shrinkage. It’s often around 30% or more, so it’s worth measuring your own.

To account for it, divide the agents you need on the phones by the share of time they’re actually available:

14 agents ÷ (1 − 0.30) = 20 agents scheduled

So in our example, you’d schedule 20 agents to have 14 on the phones at any given moment.

Step 6: Build the schedule

Now match people to the forecast, block by block.

• Follow the demand curve. Schedule more agents during busy periods and fewer during quiet ones, using staggered start times rather than having everyone start at once.
• Plan breaks and lunches around peaks. Avoid sending several agents to lunch during the busiest hour.
• Use a mix of shift types. Full-time, part-time, and split shifts help cover peaks without overstaffing quiet times.
• Schedule off-phone time during slow periods. Put training, coaching, and meetings in your quietest blocks.
• Publish schedules early. Agents value predictability. Posting schedules at least two weeks ahead helps them plan their lives, which supports retention.

Step 7: Manage the day

Even good forecasts are never perfect. During the day:

• Watch the real-time dashboard for growing queues or long waits.
• Have a plan for spikes: move agents off training, delay meetings, or offer voluntary overtime.
• Have a plan for slow periods: use the time for coaching, training, or catch-up work, or offer voluntary time off.
• Track schedule adherence: if agents aren’t logged in when scheduled, even a perfect schedule fails.

Step 8: Review and improve

Each week, compare your forecast to what actually happened. Where was it off, and why? Over time, your forecasts will get more accurate, and your staffing will get more efficient.

When to use workforce management software

Spreadsheets work for small teams. As you grow, workforce management (WFM) software can forecast automatically, build optimized schedules, track adherence in real time, and handle shift swaps and time-off requests. Many contact center platforms include basic WFM tools, and dedicated WFM software becomes worthwhile for larger teams.

Common mistakes to avoid

• Staffing to the raw workload. You always need more agents than contacts × handle time suggests.
• Forgetting shrinkage. Scheduling the number you need on the phones guarantees you’ll be short.
• Planning by the day instead of by the hour. Daily totals hide the peaks that cause long waits.
• Running agents at full capacity for weeks. Very high occupancy leads to burnout, absences, and turnover.
• Never checking the forecast against reality. Forecasts improve only when you measure how accurate they were.

What to read next

• Reading your dashboard: how to track service level and occupancy
• Reducing burnout and turnover: why overstretched schedules cost more than they save
• Contact Center Glossary: plain definitions of staffing terms