Phones

How many BDC agents do you need on the phones?

Enter your busiest hour’s calls, how long they take and how fast you want them answered. The calculator uses Erlang C, the model call centers staff phones with, then adds time for breaks and lead follow-up.

FreeNo sign-upYour numbers stay in your browserAbout 2 minutes

Example numbers are filled in so you can see how it works. Replace them with your store’s: nothing you type leaves your browser.

Your busiest hour

Inbound calls in that hour

From call tracking: the hour with the most calls, on your busiest day.

Average talk time

After-call work

Notes, CRM updates and booking after each call.

Your answer target

Answer this share of calls

Within this many seconds

80% within 20 seconds is a widely used call-center target. Pick one you can hold.

Planning

Paid time agents aren’t available

Breaks, training, meetings and time off. Use your own figure.

BDC hours open a day

Lead follow-up (optional)

New internet leads a day

Follow-up time per lead a day

Calls, texts and emails on each new lead.

Staffing your busiest hour

Overflow and after-hours calls can go to voice AI. Compare AI voice assistants

See the breakdown

How we work it out

Erlang C is the standard queueing model for staffing phone lines. From the calls in an hour and the time each one takes, it works out how likely a caller is to wait, and for how long, with any number of agents. We add agents until your target is met.

Erlang C assumes every caller waits in line. Real callers hang up, so treat the result as the minimum for that hour and watch your abandoned calls.

Scheduled staff adds the paid time agents aren’t available. Lead follow-up is spread across your open hours.

Workload: Calls in the hour times talk and after-call time, in agent-hours. 60 calls of 5 minutes is 5 agent-hours.
Answered within target: The share of callers who reach an agent within your seconds target.
Average wait: How long callers wait on average, counting the ones answered straight away.
Time on calls: How much of each agent’s hour goes to calls. Very high numbers leave no room for spikes, follow-up or breaks.

What moves the number

Staff to the hour, not the dayCalls bunch into a few hours. Shift start times and lunches around your busiest hours before you hire.What a BDC does
Send overflow to voice AIPasch Group’s Digital Voice Assistants report found an eight-rooftop group went from 9 BDC staff to 2 after adding voice AI.Read the report
Cut after-call workEvery minute of notes and CRM updates is a minute of workload. Templates and integrations shrink it.See what missed calls cost

Questions

What is Erlang C?

A queueing formula, first published by the Danish engineer A. K. Erlang in 1917, that call centers use to work out how many agents they need to answer a given volume of calls within a target time.

Why schedule more people than the calculator says?

The agent number is how many people need to be on the phones in that hour. Breaks, training, meetings and time off take people off the phones, so you schedule more to keep that many available.

What answer target should a dealership use?

Pick one you can hold in your busiest hour. Many call centers use 80% within 20 seconds. For a dealership every unanswered sales or service call is a lost opportunity, so faster is better if the staffing cost makes sense.

Sources

Erlang C queueing model (A. K. Erlang, 1917)
Digital Voice Assistants: Marketplace Report, Pasch Group (2025)
AI and Dealership Staff, Pasch Group (October 2026)

Updated October 11, 2026

Go deeper

More tools

Want a second pair of eyes on your numbers?

Tell us what you’re seeing and we’ll help you find what’s worth fixing first. No pitch.

Talk to us All tools