Shrinkage build-up calculator
Build shrinkage up from its component parts so you can see what’s driving it — and convert a net agent requirement into a gross scheduled headcount.
Components
Enter each component as a % of paid hours. Off-phone shrinkage compounds multiplicatively, not additively — this calculator handles that for you.
Gross-up calculation
Results
Component breakdown
| Component | Input % | Effective % |
|---|---|---|
| Total | — |
1 − (1 − a)(1 − b)(1 − c)…. The “effective %” column shows each component’s contribution after that compounding.
How it works
Shrinkage is the share of paid time your agents are not available to handle contacts — breaks, training, coaching, meetings, system time and absence. It is the bridge between the net requirement an Erlang calculation gives you (bodies needed on the phones) and the gross headcount you actually have to schedule and recruit. This calculator builds shrinkage up from its component parts so you can see what's driving it, then grosses a net requirement up to a roster figure.
Common questions
What's a normal shrinkage rate?
Including paid leave, training, coaching, breaks, meetings and unplanned absence, a healthy operation runs around 28–35%. Above 40% usually means hidden time the agents themselves don't realise they're consuming; below 25% often means under-investment in training or coaching.
What's the difference between net and gross requirement?
Net requirement is the number of agents you need actually handling contacts in an interval (what Erlang gives you). Gross is net divided by one minus shrinkage — the larger number you must roster and recruit so that, after all the off-phone time, the net are still on the phones.
Related: Shrinkage: the planner’s hardest input · Scheduling guide · Erlang C