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Focus Group Size Calculator

Work out focus group size instantly with clear inputs, formula shown and shareable results.

About Focus Group Size Calculator

Focus group size is a trade-off between diversity of view and individual airtime. Eight participants in a ninety minute session share 11.25 minutes each on average, which is workable; twelve participants leaves 7.5 minutes and the quieter members effectively silent. Four groups of eight gives 32 participants and six hours of recorded discussion.

Formulas

Airtime per participant

minutes = session length / participants per group

Total participants

total = participants per group x number of groups

Worked example

With the default values below, Focus Group Size Calculator returns Total Participants of 32. Change any input above and every figure here is recalculated in your browser.

Inputs used

Participants per groupminimum 1
8
Number of groupsminimum 1
4
Session lengthminimum 1 min
90 min

Results

Total Participants
32
Average Airtime Per Participant
11.3 min
Total Session Hours
6.00 h
Group Size Assessment
Ideal range for balanced participation

Step by step

  1. 1Values used
  2. 2Airtime per participant
  3. 3Total participants
  4. 4Total Participants= 32
  5. 5Average Airtime Per Participant= 11.3 min
  6. 6Total Session Hours= 6.00 h
  7. 7Group Size Assessment= Ideal range for balanced participation

Assumptions and limits

  • The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

What is the ideal focus group size?

Six to eight for most topics. Sensitive subjects work better with four to six, and market research sometimes uses ten to twelve accepting shallower input.

How many groups are needed?

Usually three to five per distinct population segment, continuing until no new themes emerge - the same saturation logic as interviews.

Related Calculators

Focus Group Size Calculator – Calculate Total Participants