How many agents does your call volume take?
Erlang C has one right answer per configuration, and almost nobody publishes it. These pages show the worked answer for each rung of the volume ladder: agents on the phones, scheduled headcount after shrinkage, and what one agent either way does to the queue.
The ladder at a glance
Same assumptions on every rung (4-minute handle time, 80/20 target, 30 percent shrinkage), so the one thing this table isolates is scale. Notice the pooling gain: 16 agents per 100 calls at the bottom, 7.4 at the top.
| Calls / hour | Offered load | Agents on phones | Scheduled | Agents / 100 calls | Occupancy | Page |
|---|---|---|---|---|---|---|
| 25 | 1.7 erlangs | 4 | 6 | 16 | 41.7% | Full math → |
| 50 | 3.3 erlangs | 6 | 9 | 12 | 55.6% | Full math → |
| 100 | 6.7 erlangs | 10 | 15 | 10 | 66.7% | Full math → |
| 200 | 13.3 erlangs | 17 | 25 | 8.5 | 78.4% | Full math → |
| 500 | 33.3 erlangs | 39 | 56 | 7.8 | 85.5% | Full math → |
| 1000 | 66.7 erlangs | 74 | 106 | 7.4 | 90.1% | Full math → |
By calls per hour
How many agents do you need for 25 calls an hour?
4 on the phones, 6 scheduled
See the math80/20 · 4min AHTHow many agents do you need for 50 calls an hour?
6 on the phones, 9 scheduled
See the math80/20 · 4min AHTHow many agents do you need for 100 calls an hour?
10 on the phones, 15 scheduled
See the math80/20 · 4min AHTHow many agents do you need for 200 calls an hour?
17 on the phones, 25 scheduled
See the math80/20 · 4min AHTHow many agents do you need for 500 calls an hour?
39 on the phones, 56 scheduled
See the math80/20 · 4min AHTHow many agents do you need for 1000 calls an hour?
74 on the phones, 106 scheduled
See the math90/30 · 4min AHTHow many agents do you need for 100 calls an hour at a 90/30 service level?
11 on the phones, 16 scheduled
See the math80/20 · 6min AHTHow many agents do you need for 100 calls an hour with a 6-minute handle time?
14 on the phones, 20 scheduled
See the mathBy calls per day
Daily volume needs one extra assumption: how the calls spread across the day. These pages plan for a busiest hour of about 15 percent of daily volume over an 8-hour window, and show the peak against the average so the intraday gap is visible.
How many agents do you need for 100 calls a day?
3 at peak, 5 scheduled
See the math500 / dayHow many agents do you need for 500 calls a day?
8 at peak, 12 scheduled
See the math1000 / dayHow many agents do you need for 1000 calls a day?
14 at peak, 20 scheduled
See the math2000 / dayHow many agents do you need for 2000 calls a day?
25 at peak, 36 scheduled
See the mathThe method behind every rung
Every page runs the same computation: calls per hour times handle time gives the offered load in erlangs, Erlang C gives the probability a call waits at each agent count, and the answer is the smallest team that clears the service level target. Shrinkage then converts agents on the phones into bodies on the schedule. The numbers are computed at build time, never copywritten, so the headline, the tables, and the derivation always agree.
To run the same math on your own inputs, use our Erlang C calculator, work out your real shrinkage with the shrinkage tool, and build an interval-level forecast with the forecast tool. If your question is coverage hours rather than call volume, start from the coverage math library instead.
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