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Queue recovery time calculator

When a queue builds, how long until it clears? Enter the current queue depth, arrival rate, AHT, and agents available to get a recovery time estimate — and find out how many agents you need to clear it faster.

Queue recovery time calculator

Given a current queue depth and arrival rate, how long will it take your agents to clear it?

50 contacts
1 contacts500 contacts
120/hr
10/hr1000/hr
5 min
1 min30 min
22 agents
1 agents200 agents

Queue clears in

21 min

at current staffing and arrival rate

Service capacity

264/hr

vs. 120/hr arriving

Effective occupancy

45%

target: below 85%

Faster recovery options

Break even (queue stops growing)10 agents
Clear queue within 15 min27 agents
Clear queue within 30 min19 agents

How queue recovery time is calculated

1

Service capacity = agents × (60 ÷ AHT)

How many contacts your current agent team can complete per hour. Example: 22 agents × (60 ÷ 5 min) = 264 contacts/hour.

2

Net drain rate = service capacity − arrival rate

How many contacts per hour the queue is shrinking. Example: 264 − 120 = 144 contacts/hour = 2.4/minute. If this is zero or negative, the queue is growing.

3

Queue clear time = queue depth ÷ net drain rate per minute

Example: 50 contacts ÷ 2.4/minute = 20.8 minutes. This assumes the arrival rate stays constant — if volume is still spiking, the actual clear time will be longer.

Simplification note: This model assumes contacts arrive at a constant rate during the recovery period. Real queues have variable arrival rates — the result is a useful planning estimate, not a precise prediction. For a more accurate picture of how queue depth affects individual wait times, use the Erlang C model.

Queue recovery questions

How do you calculate how long it takes a contact centre queue to clear?

Queue clear time = queue depth ÷ net drain rate. Net drain rate = (agents × 60/AHT) − arrival rate. If arrival rate ≥ service capacity, the queue cannot clear at current staffing.

What happens if agents cannot clear the queue fast enough?

If occupancy is at or above 100%, the queue grows indefinitely. To stop growth: add agents (break recalls, overtime, overflow routing), reduce arrival rate (IVR self-service, proactive outbound), or reduce AHT where possible. The minimum agents to stop growth = arrival rate ÷ (60 ÷ AHT).

What is a good target for queue recovery time in a contact centre?

Most operations target recovery within 15–30 minutes of a spike. This is achievable by keeping 2–3 agents in reserve on break, ready to be recalled. A recovery window longer than 30 minutes typically means the operation is running too lean — not enough flex capacity to absorb realistic volume variation.

Related calculators and guides

Build schedules that prevent queue build-up

The free calculator sizes the recovery problem from a single queue event. Turnella lets you build shift schedules that match headcount to forecast demand interval by interval, reducing the frequency and severity of queue build-up.

Open the full app →