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2026-03-07

Why PDF-to-Excel Rankings Flip Across Input Methods

PDF-to-Excel results vary by upload limits and text vs visual parsing. Use structure metrics and fixed schemas for fair evaluation.

Why PDF-to-Excel Rankings Flip Across Input Methods

Even so, “PDF → Excel table extraction” can still look poorly structured.
Some systems extract digital text only and drop image elements.
Some systems describe visual analysis for PDFs under 100 pages.
Some routes add limits, like a 50MB inline cap.
These differences can shift perceived rankings across systems.
An evaluation method for document tables often helps more than “who is smarter.”

TL;DR

  • Input limits and parsing routes vary across systems, which changes PDF table extraction outcomes.
  • Structural errors can drive costs, so structure metrics and schema checks help explain failures.
  • Run a repeatable test harness with metrics, schema-fixed output, and validation retries.

Example: A team exports a table and sees shifted columns. They rerun extraction with layout hints. They compare outputs across tools. They keep the version that needs the least manual cleanup.

TL;DR

  • Core issue: Excel-like extraction from multi-page PDFs is sensitive to test conditions.
    The input method can affect outcomes.
    Text-only parsing versus visual analysis can change results.
  • Why it matters: Correct text can still produce unusable spreadsheets.
    Common issues include missing rows and misaligned columns.
    Broken merged cells can also raise cleanup time.
    Metrics like GriTS, TEDS, and DAR can separate structure quality.
  • What to do: Use one PDF with a bundle of controls.
    Combine structural metrics, schema-fixed output, and automated validation.
    This can keep rankings explainable when conditions change.

Current state

PDF input is not only a “works or doesn’t work” question.
Official documentation indicates several products accept PDF input.
The limits and interpretations vary across systems.
OpenAI’s file upload FAQ states 512MB per file.
It also states a 2M token cap per document file.
That supports long PDFs as inputs.
It does not, by itself, imply accurate table structuring.

A major branch is how the system interprets the PDF.
One approach treats the PDF as text.
Another approach also uses layout or visual elements.
This research summary notes ChatGPT may extract digital text only on general plans.
It also notes image elements may be discarded.
By contrast, Claude is summarized as supporting visual element analysis.
That summary limits this to PDFs under 100 pages.
Even a 4-page PDF can vary by scan status and layout.
Merged cells and graphic headers can further change results.

On the Gemini side, the input route can be the first constraint.
That can change test conditions for the same document.
Copilot details are unclear from this snippet.
We only state that PDF support exists and constraints vary.

Analysis

PDF-to-Excel comparisons can be hard to interpret.
The task combines three linked problems.
First, you detect the table region.
Second, you recognize the table structure.
Third, you extract the cell contents.
Stable text generation can still fail at structure recognition.
That can make the spreadsheet hard to use.

A single “accuracy” score can be misleading.
It can hide where errors originate.
Structure-centric metrics are used in technical materials.
GriTS compares tables in a grid-like form.
TEDS uses tree-edit distance similarity ideas.
DAR uses precision, recall, and F1 over adjacency relations.
PDF-to-Excel often fails with missing or duplicate rows.
Column alignment errors are also common.
Merged cell breakage can be especially disruptive.
It can help to track structure and content scores separately.
That can clarify why a ranking changed across conditions.

Practical application

Workflows can focus on detecting failures and retrying.
That can reduce dependence on one-shot perfection.
This material includes evidence for JSON Schema-based structured outputs.
The OpenAI API supports response_format: { type: "json_schema" }.
It also specifies a refusal field.
That can help detect refusals or schema mismatches in code.
Gemini documentation notes Structured Outputs follow schema key order.
That can help lock column order for table extraction.
This snippet does not confirm that official guides recommend CSV as best practice.

Example: If you are extracting tables from a multi-page PDF, avoid direct Excel writes.
Define an intermediate schema like tables[] -> rows[] -> cells[].
Include row_index, col_index, text, rowspan, and colspan.
Validate that row_index is contiguous.
Check that merged cells do not overlap.
Check that header structure stays consistent across pages.
If validation fails, retry with a revised prompt.
This loop can surface repeated merged-cell failure modes.

Checklist for Today:

  • Split tests by whether the PDF has a text layer or is scanned.
  • Enforce JSON Schema, and retry on schema mismatches or refusal.
  • Report at least one of GriTS, TEDS, or DAR, with structure and content separated.

FAQ

Q1. For evaluating PDF → Excel table extraction, which metric should I look at first?
A1. If structure matters most, consider GriTS or DAR first.
These focus on row and column relationships.
If values also matter, add a content-oriented view.
GriTS content scoring or TEDS can help.

Q2. Is the right answer “extract as CSV,” or is JSON the right answer?
A2. This research did not confirm “CSV” as an official best practice.
It did confirm schema-fixed JSON outputs in official guides.
A validation loop can reduce parsing failures.

Q3. If upload limits suggest long documents are supported, why are results unstable?
A3. Limits mainly determine whether input is accepted.
Table extraction depends on structure restoration.
Some systems may extract digital text only.
Some systems may apply visual analysis under certain conditions.
Different interpretations can produce different outputs.

Conclusion

PDF-to-Excel extraction mixes input interpretation and structure restoration.
It also benefits from validation and retries.
Spec limits like 512MB, 2M tokens, 50MB inline, and 100 pages inform acceptance.
They do not fully predict table structure quality.
Structure metrics like GriTS, TEDS, and DAR can make evaluations more explainable.
Schema-fixed outputs can help stabilize downstream parsing.

Further Reading


References

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