THE NUMBERS, EXPLAINED
How to use this calculator.
Unique positive integer IDs represent meaningful content units. Reports supplied order differences only; it does not parse PDF tags or determine the intended semantics.
Start with your inputs
Enter expected reading order element ids, observed pdf reading order element ids. Keep amounts in the units shown on each field. The example is a starting point, not a recommended value.
| Input | Example value |
|---|---|
| Expected reading order element IDs | 1,2,3,4 |
| Observed PDF reading order element IDs | 1,3,2 |
A worked example
With the example inputs above, expected ids omitted from observed order is 4. Change the inputs to explore your own scenario.
| Result | Example answer |
|---|---|
| Expected IDs omitted from observed order | 4 |
| Unexpected observed IDs | |
| Pairwise order inversions (count) | 1 |
How this is calculated
Expected IDs omitted from observed order
Find expected elements absent from the observed sequence.
Unexpected observed IDs
Find observed elements absent from the expected sequence.
Pairwise order inversions (count)
Count observed pairs reversed relative to their expected order.
Symbols and units
- a
- Expected reading order element IDs
- b
- Observed PDF reading order element IDs
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
Unique positive integer IDs represent meaningful content units. Reports supplied order differences only; it does not parse PDF tags or determine the intended semantics.
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 IDs omitted from observed order; Unexpected observed IDs; Pairwise order inversions (count). 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: Unique positive integer IDs represent meaningful content units. Reports supplied order differences only; it does not parse PDF tags or determine the intended semantics.
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
W3C PDF3: Correct Reading and Tab Order ↗
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 →