What shrinkage is
Shrinkage is the percentage of paid, scheduled time during which agents are not available to handle contacts. It covers planned losses such as breaks, lunches, team meetings, coaching sessions, and training, and unplanned losses such as sick time, lateness, system outages, and early departures. Some teams also count vacation here; others remove vacation before building schedules. Either convention works as long as you are consistent about which hours your staffing requirement is being compared against.
Shrinkage is the single most underestimated number in workforce management. A requirement of 70 productive agents at a true shrinkage of 30 percent means scheduling 100 people. A planner who quietly assumes 20 percent schedules 88 and has built a 12-agent shortfall into every single interval before the first call arrives. Service level misses that get blamed on a volume spike are very often a shrinkage estimate that was wrong by five points.
The formula: why you multiply instead of add
The naive approach adds the categories: 12 percent absence plus 8 percent breaks plus 5 percent training plus 6 percent meetings equals 31 percent. The problem is double counting, an agent who is out sick is not also taking a break that day. The correct stack is multiplicative: total shrinkage equals one minus the product of (one minus each component). In the example, one minus 0.88 times 0.92 times 0.95 times 0.94 gives about 27.7 percent, not 31 percent. Each layer of lost time only applies to the hours that survived the previous layers.
Written out as the gross-up: scheduled agents required equals productive agents required divided by one minus total shrinkage. At 27.7 percent shrinkage, every 100 productive agents you need means scheduling about 139. That divisor is exactly how QueuePilot converts interval requirements into schedule requirements in its Forecast Lab.
How to choose your component values
Measure, do not guess. Pull a month of schedule data and bucket every non-queue state: absence and lateness typically run 5 to 12 percent, breaks and lunches 8 to 12 percent of paid time, meetings and coaching 4 to 8 percent, and training anywhere from 2 percent in steady state to 15 percent during a product launch or new-hire wave. Separate planned from unplanned components, because you can schedule around a meeting but only forecast absence statistically. Most mature voice operations land between 25 and 35 percent total; if your stack computes under 20 percent, you are probably missing a category rather than running an unusually disciplined floor.
Revisit the number quarterly. Shrinkage drifts with seasonality, attrition waves, and policy changes, and a stale shrinkage assumption silently corrupts every staffing calculation downstream, which is why QueuePilot treats shrinkage as a first-class forecasting assumption you can see and challenge rather than a constant buried in a spreadsheet.
Frequently asked questions
What is a normal shrinkage percentage for a call center?
Most contact centers run between 25 and 35 percent total shrinkage once breaks, meetings, training, coaching, and absence are honestly counted. Below 20 percent usually means a category is being missed; above 40 percent usually signals an absence or off-queue discipline problem worth investigating.
Why multiply shrinkage components instead of adding them?
Adding double counts overlapping losses, since an absent agent cannot also be in training. The multiplicative stack, one minus the product of one minus each component, applies each loss only to the hours that survived the previous losses, which slightly lowers the total and matches how the hours actually disappear.
How does shrinkage change how many agents I schedule?
Divide the productive requirement by one minus shrinkage. Needing 70 agents on the queue at 30 percent shrinkage means scheduling 100. Use our staffing or Erlang C calculator to get the productive requirement first, then apply the gross-up.
Should vacation count as shrinkage?
It depends where you remove it. If your requirement is compared against scheduled hours after vacations are subtracted, leave vacation out of shrinkage. If you compare against total paid headcount, include it. The only wrong answer is counting it in both places or neither.