Free tool

Calling capacity calculator

Set your assumptions and the model works out how many calling hours the whole team needs, then compares that with the capacity you actually have. It works for any calling programme: a telethon, a thank-a-thon, stewardship calling or a renewal round. Adjust anything and everything updates live. Nothing is saved, so experiment freely.

Assumptions

People you want to attempt to reach
people
Share of dials that get answered
%
Length of a real conversation
min
Voicemail, ring-out and notes
min
How many times you dial each person before giving up

Your team

Staff, students, volunteers and ambassadors
people
Hours each caller is on the phones
hrs
If people do more than one shift
Callers × shift length × shifts
60 hrs
Calling hours needed
88 hrs
to attempt all 1,200 people once
Hours you have
60 hrs
30 callers × 2 hr shift

Total dial attempts
1,200
Answered conversations
360
No answer / voicemail
840
Answered calls / caller-hour
4.1
Callers to clear pool
44
Hours each, current team
2.9
How the numbers are worked out

The model is deliberately simple and transparent. For every person in the pool the team makes one dial attempt, or more if you raise attempts per person. Each attempt is either answered or not:

  • attempts = pool × attempts per person
  • answered = attempts × pickup rate, each taking the average answered call length
  • unanswered = attempts − answered, each taking the time per unanswered call
  • hours needed = (answered × call length + unanswered × no-answer time) ÷ 60
  • team capacity = callers × shift length × shifts per caller

The answered calls per caller-hour figure is derived from your inputs as a sanity check, rather than being an input in its own right.

What to assume, and what the tool will not tell you

Pickup is the one number nobody can promise you. It moves with the audience, the time of day, the number people see coming up on the screen and whether they were told to expect a call, and the same list called in October and in June will not behave the same way. So run it low and run it high, and look at both rosters, rather than settling on a middle figure and planning against that alone.

My own rule of thumb when I am planning a shift is around four to five answered calls per caller per hour. If your inputs push the answered-calls-per-caller-hour figure much above five, something in the assumptions is optimistic - usually the length of the conversation, because a good stewardship call rarely comes in under ten minutes.

This is a tool for sizing a roster. It is not a forecast of income, and it says nothing about how many of those conversations end in a gift.

Jonathan May, Hubbub

Working out whether the roster is realistic?

We have run hundreds of calling campaigns with universities, colleges and schools, and we are happy to look at your numbers with you.

Book a demo Telephone campaigns