Add your CBOR file
Drop one or more .cbor files onto the converter above, or browse for them. They load into browser memory only — nothing is uploaded, so there is no size-based pricing and no server queue.
Converting a .cbor font to .xlsx repackages the same glyphs and metrics for a different delivery target. Free, private, and validated — the file never leaves your browser.
Batch files can each use a different output. Nothing uploads for local conversions.
Working inputs include camera RAW, browser-local audio/video, PDF, CBZ/CBR comics, office documents, ebooks, markup, 3D models, structured text, images, and archives.Converting a .cbor font to .xlsx repackages the same glyphs and metrics for a different delivery target. A .cbor file holds Concise Binary Object Representation data: a binary format built on the JSON data model but standardized by the IETF, with a tag mechanism that lets it carry dates, big integers, decimals and arbitrary application types without inventing a convention for each one.
An .xlsx file is a modern Excel workbook — a ZIP archive of SpreadsheetML XML parts describing sheets, shared strings, styles, and formulas. It has been Excel's default save format since 2007 and the de facto interchange format for tabular business data. For this route the practical draw is vast grid limits compared with the legacy .xls format and documented ZIP-of-XML anatomy — any ZIP and XML library can mine it, which is how in-browser conversion works here — balanced against date-as-serial-number storage causes subtle off-by-one and timezone bugs, which is worth knowing before you commit a large batch.
The practical trigger for this conversion is usually a mismatch: with .cbor, tag semantics are only as portable as the two ends' agreement on them. Switching to .xlsx buys you vast grid limits compared with the legacy .xls format, which is why it is the better fit for the standard vehicle for exchanging spreadsheets between organizations. Because the conversion runs locally, trying it costs nothing but a few seconds of compute on your own machine.
| Aspect | CBOR (.cbor) | Excel workbook (.xlsx) |
|---|---|---|
| Format type | Lossless — every pixel or sample is preserved exactly | Text-based — characters and structure, so there is no visual quality loss |
| How it stores data | every item begins with a major type in the top three bits and a length or value in the remaining five, which makes decoders small enough for microcontrollers | xl/worksheets/sheetN.xml holds rows of typed cells; text cells usually point into xl/sharedStrings.xml to avoid repetition |
| Strongest at | webAuthn and FIDO2 attestation and assertion payloads | the standard vehicle for exchanging spreadsheets between organizations |
| Weak spot | tag semantics are only as portable as the two ends' agreement on them | date-as-serial-number storage causes subtle off-by-one and timezone bugs |
| Metadata | semantic tags are read and reported; JSON and YAML targets receive their normalized textual form, since neither has a tag mechanism | docProps/core.xml carries Dublin Core creator and date fields while docProps/app.xml records the generating application and company — both ride inside the ZIP |
Drop one or more .cbor files onto the converter above, or browse for them. They load into browser memory only — nothing is uploaded, so there is no size-based pricing and no server queue.
Select .xlsx in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if XLSX is selectable, the route is real and validated.
Press Convert. The font tables are parsed and rewritten locally with fonteditor-core; glyph outlines, hinting, and kerning survive the trip.
Each result is signature-checked before the download unlocks, so a failed encode can never masquerade as a valid XLSX file. Outputs keep the original filename with the .xlsx extension.
There is no visual quality to lose — cbor is lossless-oriented and xlsx is text-oriented, so the question is structural fidelity. Text, ordering, and basic structure are preserved; complex layout, embedded objects, and styling beyond the target's model are simplified.
Yes — the .cbor file is processed inside your browser tab and never uploaded. The font tables are parsed and rewritten locally with fonteditor-core; glyph outlines, hinting, and kerning survive the trip. Close the tab and the file is gone from memory.
Excel 2007 onward, LibreOffice Calc, Google Sheets, and Apple Numbers all handle .xlsx, and nearly every data-processing library reads it. Support is equally solid on iOS and Android through the same vendors' apps.
It depends on the content: xl/worksheets/sheetN.xml holds rows of typed cells; text cells usually point into xl/sharedStrings.xml to avoid repetition. Convert one representative file first and compare before batch-processing a large set.
In .cbor, semantic tags are read and reported; JSON and YAML targets receive their normalized textual form, since neither has a tag mechanism. Re-encoding through the browser pipeline does not carry embedded metadata into the output, which doubles as a privacy scrub — check the exported file if you specifically need tags preserved.