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Use the local sample to explore the verified result and exports.
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Keep all sheets unless hidden workbook content is intentionally out of scope.
The converter does not recalculate formulas. Open the XLSX in Excel to refresh calculations.

Compatibility boundary: VBA macros cannot be retained in XLSX. Charts, images, PivotTables, external connections, conditional formatting, ActiveX/OLE objects, and exact visual styling require manual review.

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Opening Advanced without changing this neutral default does not alter the conversion.
CheckStatusEvidenceCopy
{{ row.label }}{{ row.status === 'pass' ? 'Verified' : 'Review' }}{{ row.detail }}
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An XLS workbook stores spreadsheet data in the older Excel Binary File Format, commonly associated with Excel 97–2003. XLSX uses the newer Office Open XML structure. Converting between them requires parsing the workbook and writing a new package; renaming the extension does not change the file format.

Modernization can make a workbook easier to open in current software, but it does not guarantee a pixel-perfect copy. Cell values, supported formulas, sheet order, merges, names, comments, hyperlinks, and number formats can be checked structurally. Charts, images, PivotTables, connections, embedded objects, conditional formatting, and exact styling still need a visual review in Excel.

Formula handling is a consequential choice. Preserving formulas keeps supported expressions and their stored results, but conversion does not recalculate them. Keeping cached values removes the expressions and retains only the last values saved in the source workbook. Those values may be stale if the XLS was not recalculated before it was saved.

  • Keep all sheets when hidden or very hidden content may be part of the workbook's logic.
  • Use visible sheets only when removing hidden content is deliberate and acceptable.
  • Keep the original XLS until the converted workbook has been opened and reviewed.

VBA macros cannot be carried into an XLSX file. A macro-bearing workbook needs a macro-capable format such as XLSM and an Excel-based migration path rather than ordinary XLSX conversion.

How to Use This Tool:

Work from a copy of the legacy workbook and decide which information must survive before starting the conversion.

  1. Choose one binary XLS workbook no larger than 15 MiB. Renamed HTML, XML, CSV, or XLSX files are rejected.
  2. Select All sheets unless omitting hidden sheets is an intentional part of the handoff.
  3. Choose whether Formula cells should retain supported expressions or become cached values only. The latter removes formula logic.
  4. Leave Legacy text fallback on Auto unless an older BIFF2–BIFF5 workbook lacks a usable code-page declaration and its text is decoded incorrectly.
  5. Convert, review every warning in the compatibility ledger, download the XLSX, and open it in Excel to refresh formulas and inspect visual fidelity.

Interpreting Results:

Verified means the generated XLSX reopened successfully and its supported structural inventory matched the selected conversion policy. Verified with warnings means that the structural checks passed but an intentional change or manual review item remains.

Structural verification is narrower than visual equivalence. A matching cell and formula count cannot prove that a chart, print layout, object, data connection, or style looks and behaves the same. Open the file in Excel, recalculate it, inspect representative sheets, and test any links or automation before replacing the original.

Technical Details:

The source is parsed as a binary XLS workbook, transformed according to sheet and formula policy, written as an ECMA-376 XLSX package, then reopened for comparison. A completed write alone is not accepted as proof of a usable workbook.

Transformation Core

  1. Confirm the compound binary signature and parse workbook structure, formulas, formats, and VBA presence.
  2. Inventory sheets, populated cells, formulas, merges, defined names, hidden sheets, row and column dimensions, comments, and hyperlinks.
  3. Apply the chosen sheet scope and formula policy. A legacy code-page fallback is used only when explicitly selected.
  4. Write a compressed XLSX package, reopen it, and compare the supported structures with the post-policy source inventory.
  5. Release a download only when the package reload and structural comparison succeed.

Rule Core

Choice or featureConversion ruleReview consequence
All sheetsRetain sheet order and visibility stateHidden content remains part of the workbook
Visible sheets onlyRemove hidden and very hidden sheetsNames that refer to removed sheets may also be omitted
Preserve formulasKeep supported expressions and cached resultsOpen in Excel to recalculate
Cached values onlyDelete expressions and keep stored valuesFormula logic is intentionally lost
VBA projectBlock XLSX conversionUse a macro-capable migration path
Complex visual or linked featuresDo not claim exact preservationInspect manually in Excel

The processing bounds are 100 sheets, 250,000 populated cells, a 1,000,000-cell used range per sheet, a 30 MiB generated file, and 35 seconds of conversion time. A workbook with no populated cells, no visible sheet under visible-only scope, an oversized range, or a mismatched reloaded inventory is rejected.

Privacy and Compatibility Limits:

The source XLS and generated XLSX stay in browser memory for the active page and are not uploaded, logged, or retained by the service.

  • Password-protected and encrypted workbooks are not supported.
  • VBA, ActiveX, OLE objects, and other executable or embedded features are not preserved in XLSX.
  • Charts, drawings, images, PivotTables, external data connections, conditional formatting, print settings, and exact styles may change or disappear.
  • A successful structural comparison does not prove business correctness, current formula results, or safe external links.

Worked Examples:

Preserving an archival workbook

A workbook with visible and hidden sheets, formulas, merges, comments, and defined names should use All sheets and Preserve formulas. After conversion, matching structure counts are useful evidence, but the XLSX still needs recalculation and a visual check in Excel.

Publishing visible values only

Choosing Visible sheets only and Cached values only creates a deliberately reduced workbook. Hidden sheets and formula expressions are removed, so the warnings document intended loss rather than a failed conversion.

References: