THE NUMBERS, EXPLAINED
How to use this calculator.
MAPE excludes zero observed outcomes and uses absolute observed values as denominators. Excluded rows remain explicitly identified; no replacement denominator is invented.
Start with your inputs
Enter regression predictions (units), observed outcomes (units). Keep amounts in the units shown on each field. The example is a starting point, not a recommended value.
| Input | Example value |
|---|---|
| Regression predictions (units) | 10,10,30 |
| Observed outcomes (units) | 0,20,30 |
A worked example
With the example inputs above, excluded zero-outcome row numbers is 1. Change the inputs to explore your own scenario.
| Result | Example answer |
|---|---|
| Excluded zero-outcome row numbers | 1 |
| Eligible absolute percentage errors (%) | Excluded, 50, 0 |
| MAPE over eligible rows (%) | 25 |
| Eligible observation share (%) | 66.666667 |
How this is calculated
Excluded zero-outcome row numbers
Flag observations whose percentage error denominator is zero.
Eligible absolute percentage errors (%)
Compute absolute relative error only for nonzero outcomes.
MAPE over eligible rows (%)
Average absolute relative errors over eligible rows only.
Eligible observation share (%)
Divide nonzero observed outcomes by all observations.
Symbols and units
- a
- Regression predictions (units)
- b
- Observed outcomes (units)
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
MAPE excludes zero observed outcomes and uses absolute observed values as denominators. Excluded rows remain explicitly identified; no replacement denominator is invented.
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?
Excluded zero-outcome row numbers; Eligible absolute percentage errors (%); MAPE over eligible rows (%); Eligible observation share (%). 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: MAPE excludes zero observed outcomes and uses absolute observed values as denominators. Excluded rows remain explicitly identified; no replacement denominator is invented.
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
scikit-learn model evaluation documentation ↗
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 →