Call Center Shrinkage Calculator
Contact-centre shrinkage from breaks, meetings, coaching, training, system time, absence, leave and public holidays — total shrinkage (compounded or simple sum), productive hours per agent, agents to schedule for a required number on the phones, extra headcount, what your current team delivers, and the yearly cost of shrinkage.
How it works
In-office % = in-office hours ÷ paid hours · leave % = leave days ÷ working days · compounded: productive fraction = (1 − leave%) × (1 − absence%) × (1 − in-office%) · simple sum: productive fraction = 1 − leave% − absence% − in-office% · shrinkage = 1 − productive fraction · agents to schedule = agents required ÷ productive fraction (rounded up)
Shrinkage is every paid hour an agent is not available to handle contacts. It splits into out-of-office time — annual leave, public holidays, other paid leave and unplanned absence, which remove whole days — and in-office time such as breaks, coaching, meetings, system outages and other off-phone work, which erode the days that are worked. Because in-office time only happens on days the agent is present, the compounded method multiplies the parts; many spreadsheets and workforce tools simply add every part as a share of paid time, which gives a slightly higher figure, and you can switch between the two. Enter weekly items in hours a week or minutes a day. Typical totals are 25–35%, and the figure matters because Erlang C tells you how many agents must be logged in, not how many to employ: dividing by the productive fraction (never adding the percentage on top) turns 47 required into 69 scheduled. Under More options you can check what your current headcount really delivers, put a cost on shrinkage, and see how many agents a lower target would save. Under-estimating shrinkage is the most common cause of chronic service-level misses, and trimming coaching to fix it usually backfires through higher handle times and attrition.
Worked example
Forty paid hours with 2.5 h breaks, 1.5 h meetings, 2 h training and 1 h system time is 7 ÷ 40 = 17.5% in-office shrinkage; 30 leave days in 260 (11.5%) and 6% absence compound to 16.8% out of office. The productive fraction is 0.885 × 0.94 × 0.825 = 0.686, so total shrinkage is 31.4% and 47 agents on the phones need 47 ÷ 0.686 = 68.5, rounded up to 69 scheduled — 22 extra. Added up simply, the same parts give 11.5% + 6% + 17.5% = 35.0% and 73 agents.
Sources: Call Centre Helper — How to calculate contact centre shrinkage
Frequently asked questions
Is lunch shrinkage?
Only if it is paid. Unpaid lunch is outside paid hours and should be excluded from both the shrinkage hours and the paid hours.
Should occupancy be included?
No — occupancy (idle time between calls) is a separate measure already built into the Erlang C result; adding it here double-counts.
Compounded or simple sum — which is right?
Compounding is more accurate: an agent who is on leave cannot also be in a team meeting, so in-office time should only apply to days actually worked. Simple addition overstates shrinkage a little and is still common in spreadsheets. Pick the one your planning tool uses so the numbers match, and be consistent over time.
Why divide by (1 − shrinkage) instead of adding the percentage?
With 30% shrinkage only 70% of each scheduled agent is on the phones. 70 required agents × 1.30 = 91 scheduled gives just 63.7 on the phones; 70 ÷ 0.70 = 100 scheduled gives the full 70.
What shrinkage is normal?
Most contact centres run between 25% and 35%, and industry benchmark reports put the average near a third. Below about 20% is usually an under-count; above 35–40% points to high absence or a heavy meeting and training load.
Related calculators
Workforce planning estimate; local employment law, union agreements and your own historical data should govern actual schedules and targets.