What is shrinkage in a contact centre?
Shrinkage is the gap between who's on your roster and who's actually on the phones. If you've ever looked at your schedule and thought "I rostered 12 people, so why are only 8 taking calls?" then you've experienced shrinkage.
Every contact centre has it. Nobody has zero shrinkage because agents are human. They take breaks, attend meetings, get training, go on leave and call in sick. All of those things eat into the time they're available to take calls.
The problem isn't that shrinkage exists. The problem is when you don't account for it in your staffing plan. If your Erlang C calculator says you need 14 agents on the phones, and you roster exactly 14, you're going to be short. Some of those 14 will be on break, in a coaching session, or home with the flu.
The simple version
Shrinkage tells you what percentage of your rostered agents are unavailable at any given time. At 30% shrinkage, only 7 out of every 10 rostered agents are on the phones. The other 3 are somewhere else.
What counts as shrinkage?
Shrinkage splits into two categories: things that happen inside the centre and things that happen outside it.
Internal shrinkage (agents are at work, but not on calls)
- Morning tea, lunch, afternoon tea
- Team meetings and huddles
- Training sessions
- Coaching and 1:1s with their team leader
- System downtime or tech issues
- Admin tasks, emails, follow-ups
External shrinkage (agents aren't at work at all)
- Annual leave and personal leave
- Sick days
- Public holidays
- Late arrivals and early departures
- Unplanned absences
- Workers' compensation
How to calculate shrinkage
The formula is straightforward:
In practice, most teams track this over a week or a month. Add up all the time agents spent on non-call activities (breaks, meetings, leave, sick days) and divide by the total rostered hours.
You have 10 agents, each rostered for 38 hours per week. That's 380 total rostered hours.
Each agent takes 1 hour of breaks per day (5 hours/week), plus 1 hour of meetings per week. Two agents are on leave this week. One called in sick for a day.
Internal shrinkage: 10 agents x 6 hours (breaks + meetings) = 60 hours
External shrinkage: 2 agents x 38 hours (leave) + 1 agent x 7.6 hours (sick day) = 83.6 hours
That's a heavy week. On a normal week without the leave and sick day, it would be closer to 16% (internal only).
The mistake everyone makes
The most common error in workforce planning is adding shrinkage as a percentage on top of agents needed, instead of dividing by it.
Right: "I need 14 agents. With 30% shrinkage: 14 / (1 - 0.30) = 20 agents." This is the correct calculation.
The difference is 2 agents. That might not sound like much, but at peak time it's the difference between hitting your service level and watching the queue blow out.
What's a healthy shrinkage rate?
| Shrinkage % | What it means | Typical cause |
|---|---|---|
| 20-25% | Low. Efficient operation with minimal leave. | Small team, low turnover, limited meeting load |
| 25-30% | Healthy. Agents get breaks, training and coaching. | Well-managed centre with normal leave patterns |
| 30-35% | Industry standard. Most centres sit here. | Average leave, regular training, seasonal sickness |
| 35-40% | High. Worth investigating. | High absenteeism, excessive meetings, or peak leave season |
| 40%+ | Red flag. You're losing nearly half your roster. | Attrition spike, morale issues, or poor scheduling |
If you don't track your own shrinkage yet, start with 30%. It's a safe middle ground for most teams. Once you have a few weeks of data, adjust to your actual number.
How to reduce shrinkage (without cutting corners)
Some shrinkage is unavoidable and healthy. Agents need breaks. Teams need training. People get sick. The goal isn't zero shrinkage. It's removing the waste without cutting the things that keep your team effective.
- Track it by category. A single shrinkage number is useless for action. Break it into internal vs external, then into specific causes. You can't fix "37% shrinkage" but you can fix "team meetings running 20 minutes over schedule every week."
- Stagger breaks around peak times. If your busiest period is 10am-12pm, don't schedule four agents on break at 10:30. Use your day planner to see where demand peaks, then schedule breaks in the valleys.
- Audit your meeting load. How many hours per week does each agent spend in meetings? Is every meeting necessary? Could a 30-minute huddle replace a 60-minute sit-down?
- Track sick leave patterns. Consistent Monday or Friday absences suggest a culture issue, not a health issue. Address it directly.
- Plan for leave. Don't let multiple agents book the same week off during your busiest season. Set a maximum concurrent leave policy and stick to it.
How shrinkage connects to staffing
Shrinkage is one of the key inputs to any staffing calculator. Without it, your calculation tells you how many agents need to be on the phones, but not how many you need on the roster. With shrinkage factored in, you get the real number.
The QueueMath Workforce Planner builds shrinkage into every calculation automatically. You set your shrinkage percentage, and the tool adjusts agent requirements upward to account for the reality of your floor.
See the impact of shrinkage on your team
Enter your call volume, handle time and shrinkage percentage. See exactly how many agents you need, and where your day is exposed.
Open the free calculatorKey takeaways
- Shrinkage is the percentage of rostered time agents aren't available for calls.
- At 30% shrinkage, only 7 out of 10 rostered agents are on the phones.
- Always divide by (1 - shrinkage), never add shrinkage on top. The maths matters.
- 25-35% is the normal range. Track yours and adjust your planning accordingly.
- Reduce shrinkage by auditing meetings, staggering breaks and managing leave, not by cutting training or breaks.