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Shrinkage Calculator

Turn planned and unplanned off-phone time into one planning shrinkage percentage, and see the headcount uplift it forces on every staffing requirement.

Live · updates as you type

Shrinkage inputs

Results update live as you type.

Input method
hrs

All paid hours in the period

hrs

Breaks, training, coaching, meetings

hrs

Absence, sickness, late logins, system downtime

agents

From Erlang C or your interval requirement

Total shrinkage
30.0%

Only 70.0% of paid time is available to take contacts.

Staff to schedule
143agents

Base staff ÷ (1 − total shrinkage).

Planned
20.0%
Unplanned
10.0%
Extra heads needed
43agents
Breakdown
Productive time
70.0%
Planned shrinkage
20.0%
Unplanned shrinkage
10.0%
2,800 productive hours are left out of 4,000 scheduled hours.

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Results are estimates for planning purposes only and should not replace professional workforce management judgment.

Shrinkage is the share of paid time that agents are not available to handle contacts. It is the single biggest reason a staffing requirement of 100 agents on the phone turns into 140 people on the payroll. Get it wrong and every downstream number, roster, budget, hiring plan, is wrong with it.

Planned vs unplanned

Planned shrinkage is time you schedule on purpose: breaks, lunches, team meetings, coaching, training, one-to-ones and project work. Unplanned shrinkage is time you lose without choosing to: sickness, unauthorised absence, late logins, early logouts, long after-call spillover and system outages. Splitting the two matters because they are managed by different people, planning owns the first, operations owns the second.

The formula

  • Total shrinkage % = (planned hours + unplanned hours) ÷ total scheduled hours × 100
  • Staff to schedule = base staff ÷ (1 − total shrinkage %)

Notice that you divide rather than multiply. Adding 30% to a 100-agent requirement gives 130, but you actually need 100 ÷ 0.70 = 143. That gap between the two methods is the most common shrinkage mistake in contact centre planning, and it understaffs you by roughly 10% at typical shrinkage levels.

What a healthy number looks like

Most contact centres land between 25% and 35% total shrinkage. Below 20% usually means something is missing from the calculation, often training or the unpaid portion of breaks. Above 40% is worth investigating: it is either a genuine absence problem or a period distorted by a one-off training programme. Track planned and unplanned separately over time; a rising unplanned figure is an early warning sign of burnout and attrition long before either shows up in your exit interviews.

Practical tips

  • Use the same period for every input, mixing a week of absence with a month of scheduled hours skews everything.
  • Decide once whether unpaid lunches are in or out of scheduled hours, and document it.
  • Forecast shrinkage by interval, not just as a daily average: mid-afternoon coaching blocks hurt far more than the daily number suggests.

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