THE NUMBERS, EXPLAINED
How to use this calculator.
Matched timestamps use one continuous origin, allowing shifts past midnight. Reports overall R7 interpolated median and 90th percentile, plus mean ticket time by supplied service-period identifier.
Start with your inputs
Enter order times (minutes from common start), completion times (minutes from common start), service-period numeric identifiers. Keep amounts in the units shown on each field. The example is a starting point, not a recommended value.
| Input | Example value |
|---|---|
| Order times (minutes from common start) | 0,5,10,15 |
| Completion times (minutes from common start) | 10,25,40,55 |
| Service-period numeric identifiers | 1,1,2,2 |
A worked example
With the example inputs above, median ticket time (min) is 25. Change the inputs to explore your own scenario.
| Result | Example answer |
|---|---|
| Median ticket time (min) | 25 |
| 90th-percentile ticket time (min) | 37 |
| Mean by period in ascending code order (min) | 15, 35 |
How this is calculated
Median ticket time (min)
Sort durations and linearly interpolate at zero-based position 0.5 times n minus one.
90th-percentile ticket time (min)
Use R7 linear interpolation at zero-based position 0.9 times n minus one.
Mean by period in ascending code order (min)
Group observed durations by service-period identifier and average each group.
Symbols and units
- a
- Order times (minutes from common start)
- b
- Completion times (minutes from common start)
- c
- Service-period numeric identifiers
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
Matched timestamps use one continuous origin, allowing shifts past midnight. Reports overall R7 interpolated median and 90th percentile, plus mean ticket time by supplied service-period identifier.
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?
Median ticket time (min); 90th-percentile ticket time (min); Mean by period in ascending code order (min). 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: Matched timestamps use one continuous origin, allowing shifts past midnight. Reports overall R7 interpolated median and 90th percentile, plus mean ticket time by supplied service-period identifier.
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
NIST Engineering Statistics Handbook: Percentiles and R7 interpolation ↗
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 →