THE NUMBERS, EXPLAINED
How to use this calculator.
Historical descriptive buffer only; the observed maximum does not guarantee future appointment duration.
Start with your inputs
Enter booked appointment minutes, actual appointment minutes. Keep amounts in the units shown on each field. The example is a starting point, not a recommended value.
| Input | Example value |
|---|---|
| Booked appointment minutes | 30,30,45 |
| Actual appointment minutes | 35,25,60 |
A worked example
With the example inputs above, signed overruns by appointment (minutes) is 5, -5, 15. Change the inputs to explore your own scenario.
| Result | Example answer |
|---|---|
| Signed overruns by appointment (minutes) | 5, -5, 15 |
| Mean positive overrun (minutes) | 6.666667 |
| Buffer covering observed worst overrun (minutes) | 15 |
How this is calculated
Signed overruns by appointment (minutes)
Subtract booked minutes from actual duration.
Mean positive overrun (minutes)
Average positive overruns over all appointments, counting early finishes as zero.
Buffer covering observed worst overrun (minutes)
Report the largest observed positive overrun.
Symbols and units
- a
- Booked appointment minutes
- b
- Actual appointment minutes
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
Historical descriptive buffer only; the observed maximum does not guarantee future appointment duration.
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?
Signed overruns by appointment (minutes); Mean positive overrun (minutes); Buffer covering observed worst overrun (minutes). 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: Historical descriptive buffer only; the observed maximum does not guarantee future appointment duration.
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: Measures of the Center of the Data ↗
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 →