THE NUMBERS, EXPLAINED
How to use this calculator.
Applies your response-rate estimates to each group. Scenario adjustments are percentage points and are capped to 0–100%. Results are expectations, not guaranteed headcounts.
Start with your inputs
Enter invitations by group, expected response rates (%), low-scenario rate adjustment (percentage points), high-scenario rate adjustment (percentage points). Keep amounts in the units shown on each field. The example is a starting point, not a recommended value.
| Input | Example value |
|---|---|
| Invitations by group | 100,50 |
| Expected response rates (%) | 80,60 |
| Low-scenario rate adjustment (percentage points) | -10 |
| High-scenario rate adjustment (percentage points) | 10 |
A worked example
With the example inputs above, expected attendance is 110. Change the inputs to explore your own scenario.
| Result | Example answer |
|---|---|
| Expected attendance | 110 |
| Low scenario | 95 |
| High scenario | 125 |
How this is calculated
Expected attendance
Sum invitations × expected response fraction by group.
Low scenario
Repeat after adding the low adjustment to every rate, capped to 0–100%.
High scenario
Repeat after adding the high adjustment to every rate, capped to 0–100%.
Symbols and units
- a
- Invitations by group
- b
- Expected response rates (%)
- c
- Low-scenario rate adjustment (percentage points)
- d
- High-scenario rate adjustment (percentage points)
Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.
Assumptions and limits
Applies your response-rate estimates to each group. Scenario adjustments are percentage points and are capped to 0–100%. Results are expectations, not guaranteed headcounts.
Calculations use the values you enter. Blank or invalid inputs show an error instead of silently substituting zero. Results are displayed to useful precision; calculations retain the underlying numeric precision.
Questions about this tool
What does the result tell me?
Expected attendance; Low scenario; High scenario. The result applies to the method and inputs described above. Check the units and assumptions before using it in a decision.
Why might another calculator differ?
Differences in units, rounding, timing or model definitions can produce different answers. Compare the input definitions and the method, rather than only the final number. For this tool: Applies your response-rate estimates to each group. Scenario adjustments are percentage points and are capped to 0–100%. Results are expectations, not guaranteed headcounts.
Are my inputs stored or sent to AI?
Calculations on this page happen in your browser. The separate AI question finder sends its submitted conversation to OpenAI; these calculator fields are not sent. Favourites and recent tool names are stored locally. A shared link contains the inputs you choose to include.
Further reading
OpenStax: percentages and proportions ↗
Background reading; this does not imply endorsement or independent review of SumFizz.
Review status
Software example and browser checks are recorded in our quality report. No external expert review is claimed. Created with coding assistance; calculations run as ordinary browser code.
Read the quality report →