How many agents do you need to handle 25 calls per hour?

With a 240-second average handle time and an 80/20 target, you need 4 agents on the phones, which delivers 91.6 percent of calls answered within 20 seconds and a 10.5-second average speed of answer. At 30 percent shrinkage, that means scheduling 6 agents to reliably keep 4 available.

Why do 25 calls an hour need 4 agents when the workload is only 1.7 erlangs?

Because calls arrive randomly, not evenly. Staffing 2 agents to match the 1.7 erlangs of raw workload produces a 26 percent service level and a 545-second average wait, and even 3 agents only reaches 73 percent with a 54-second ASA. The extra capacity absorbs the natural clustering of arrivals, which is what keeps the queue short.

What occupancy should I expect with 4 agents handling 25 calls per hour?

About 41.7 percent, meaning agents are on calls well under half their logged-in time. That idleness is structural at small scale, not a productivity problem, and cutting staff to raise occupancy drops the service level sharply. Most teams at this volume blend phone duty with email, chat, or back-office work so the idle time stays productive.

Does a stricter 90/30 service level cost more at 25 calls per hour?

No. At 25 calls an hour, 4 agents on the phones already answer 91.6 percent of calls within 20 seconds, so the same team clears both an 80/20 and a 90/30 target. The upgrade is an integer-math gift at this scale, and it disappears as volume grows.

Is 25 calls an hour enough to need a dedicated call center team?

Not really. A phone-only team at this volume pays the small-queue premium all day, which is why the common setup is 6 scheduled people who share phone duty with email, chat, or back-office work, with a hard rule that the phone preempts everything else.

The call center staffing ladder

Call center staffing

How many agents do you need for 25 calls an hour?

4 agents on the phones, 6 on the schedule, and an occupancy number you will need to defend.

The short answer

Handling 25 calls an hour at a 4-minute average handle time with an 80/20 service level takes 4 agents on the phones; at 30 percent shrinkage you schedule 6.

Calls per hour: 25
Offered load: 1.7 erlangs
Agents on phones: 4
Scheduled agents: 6
Service level hit: 91.6%
Occupancy: 41.7%

Why the math lands there

Twenty-five calls an hour at a 240-second average handle time works out to 1.7 erlangs of offered load, which is only 1.7 agents' worth of raw talk time. Erlang C still calls for 4 agents on the phones to meet an 80/20 service level, and those 4 overshoot it, answering 91.6 percent of calls within 20 seconds at a 10.5-second average speed of answer. The distance between 1.7 erlangs of work and 4 bodies is the price of random arrivals at small scale.

The floor is hard. Drop to 3 agents and service level falls to 73 percent with a 54-second ASA, a level many small teams would grudgingly accept. Drop to 2, staffing to the raw workload, and the queue collapses to a 26 percent service level with a 545-second average wait. The difference between a strained queue and a healthy one is a single agent, which is why headcount conversations at this size are so tense.

To keep 4 agents on the phones through breaks, meetings, training, and sick days, schedule 6 at 30 percent shrinkage. That puts the on-phones ratio at 16 agents per 100 calls, compared with 7.4 per 100 at 1000 calls an hour, so this volume pays more than double per call for the same service level. The math will not bend, which means the real planning question is what those agents do between calls.

125 calls an hour times 240 seconds of handle time is 1.7 erlangs of offered load: 1.7 hours of phone work arriving every hour.
2Counting up from 2 agents, 4 is the first count where Erlang C clears the 80/20 target: 91.6 percent of calls answered within 20 seconds, with an average wait of 10.5 seconds.
3At 4 agents, occupancy is 41.7 percent: the share of each logged-in hour spent handling calls rather than waiting for the next one.
4Breaks, meetings, training, and absence take agents off the phones for 30 percent of paid time, so keeping 4 on the phones means scheduling 6.

One agent either way

Erlang math is a cliff, not a slope. This is the same hour with one or two agents more or fewer on the phones.

Agents on phones	Answered in 20s	Average wait	Occupancy
2	26.3%	545.5s	83.3%
3	73.2%	54s	55.6%
4the answer	91.6%	10.5s	41.7%
5	97.7%	2.2s	33.3%
6	99.5%	0.4s	27.8%

If your handle time or target differs

Agents on the phones for 25 calls an hour, across handle times and the two most common service level targets. Adjust every input live in our Erlang C calculator.

Average handle time	80/20 target	90/30 target
3 minutes	3 agents	4 agents
4 minutesthis page	4 agents	4 agents
5 minutes	4 agents	5 agents
6 minutes	5 agents	6 agents

Scheduled headcount sits above every number here: this page assumes 30 percent shrinkage, and your own rate comes out of our shrinkage tool.

What Erlang C does not tell you

The number on this page most likely to cause a fight is occupancy: 41.7 percent. Four agents handling 1.7 erlangs are on calls well under half their logged-in time, and any utilization dashboard will flag that as waste. It is not waste, it is the buffer that turns random arrivals into a 10.5-second ASA. Cut to 3 agents to make the utilization number look respectable and the service level drops from 91.6 percent to 73 percent. At this scale, low occupancy is the cost of answering quickly, and no schedule can engineer it away.

The workable answer is to stop treating this as a call center and staff it as a team that answers phones. Route email, chat, or back-office queues to the same 4 people, with a hard rule that a ringing phone preempts everything else, so the structural idle time produces something. And take the free upgrade while you are here: at 25 calls an hour, a stricter 90/30 target also needs only 4 agents. Staffing moves in whole bodies, so the tighter promise costs nothing at this volume, which is almost never true at larger ones.

What Erlang C does not price in is how fragile 4 is. One absence removes a quarter of your phone capacity and starts the day at the 3-agent tier, 73 percent and a 54-second ASA, before anything has gone wrong. The model also assumes smoothly random arrivals, but small lines get lumpy demand: a marketing send or a short outage bunches calls in ways an hourly average hides, and there is no depth at 4 to absorb the spike. Scheduling 6 covers normal shrinkage, not a bad Tuesday, so keep at least one cross-trained backstop who can log in when the queue jumps.

The agent count is the input; the schedule is the work. Turning 6 scheduled agents into shifts that follow your call curve, respect breaks, and survive swaps is what Soon builds automatically, with intraday coverage tracking when the forecast misses.

Frequently asked questions

How many agents do you need to handle 25 calls per hour?: With a 240-second average handle time and an 80/20 target, you need 4 agents on the phones, which delivers 91.6 percent of calls answered within 20 seconds and a 10.5-second average speed of answer. At 30 percent shrinkage, that means scheduling 6 agents to reliably keep 4 available.
Why do 25 calls an hour need 4 agents when the workload is only 1.7 erlangs?: Because calls arrive randomly, not evenly. Staffing 2 agents to match the 1.7 erlangs of raw workload produces a 26 percent service level and a 545-second average wait, and even 3 agents only reaches 73 percent with a 54-second ASA. The extra capacity absorbs the natural clustering of arrivals, which is what keeps the queue short.
What occupancy should I expect with 4 agents handling 25 calls per hour?: About 41.7 percent, meaning agents are on calls well under half their logged-in time. That idleness is structural at small scale, not a productivity problem, and cutting staff to raise occupancy drops the service level sharply. Most teams at this volume blend phone duty with email, chat, or back-office work so the idle time stays productive.
Does a stricter 90/30 service level cost more at 25 calls per hour?: No. At 25 calls an hour, 4 agents on the phones already answer 91.6 percent of calls within 20 seconds, so the same team clears both an 80/20 and a 90/30 target. The upgrade is an integer-math gift at this scale, and it disappears as volume grows.
Is 25 calls an hour enough to need a dedicated call center team?: Not really. A phone-only team at this volume pays the small-queue premium all day, which is why the common setup is 6 scheduled people who share phone duty with email, chat, or back-office work, with a hard rule that the phone preempts everything else.

How many agents do you need for 50 calls an hour?

Six on the phones, nine on the schedule, and an open question the math cannot answer: who owns the queue.

6 on phones · 9 scheduled · 80/20

See the math →

How many agents do you need for 100 calls an hour?

10 agents on the phones, 15 on the schedule, and a service level cliff hiding one absence away.

10 on phones · 15 scheduled · 80/20

See the math →

How many agents do you need for 100 calls a day?

Three people on the phones at peak, five on the schedule, and a rota that survives lunch.

3 on phones · 5 scheduled · 80/20

See the math →