Agents needed for 150 calls an hour
150 calls an hour with a five-minute handle time is 12.5 erlangs of work and needs 17 agents on the phones to answer 80 per cent within 20 seconds, at 74% occupancy. The table runs the same Erlang C calculation across handle times and two common targets; every row opens the calculator with those inputs so you can change anything else.
| Handle time | Erlangs | Agents for 80/20 | Occupancy at 80/20 | Agents for 90/60 | To schedule at 30% shrinkage |
|---|---|---|---|---|---|
| 180 s | 7.5 | 11 | 68% | 11 | 16 |
| 240 s | 10.0 | 14 | 71% | 14 | 20 |
| 300 s | 12.5 | 17 | 74% | 17 | 25 |
| 360 s | 15.0 | 19 | 79% | 20 | 28 |
| 420 s | 17.5 | 22 | 80% | 23 | 32 |
| 480 s | 20.0 | 25 | 80% | 26 | 36 |
| 600 s | 25.0 | 31 | 81% | 31 | 45 |
Click a handle time to open the calculator with that row's inputs.
Assumptions
- Calls arrive at random across a 60-minute interval; Erlang C with no abandonment.
- Agents shown are on the phones for the whole hour. The last column divides by 0.7 and rounds up.
- No occupancy ceiling is applied; small volumes come out under 85%, large ones above it, and the staffing requirement calculator adds the ceiling.
Frequently asked questions
- Why does 150 calls an hour need more agents than the erlangs?
- Erlangs are the average number of calls in progress. Calls bunch, so agents above that average are needed to keep queues short; the gap is the price of the service level target, and it shrinks as a share of the total at higher volumes.
- Is this per hour or per day?
- Per hour, for one hour that looks like this. A day has quiet and busy hours; the week planner spreads a daily or monthly total across intervals and adds the hours up.
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