Add your XLS file
Drop one or more .xls 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.
XLS to CBOR
Converting a .xls file to .cbor lifts the document's content out of its original format into a portable one. Free, private, and validated: the file never leaves your browser.
Private for supported formats, processed in your browser
Runs on your deviceConvert supported files
Drop XLS files here
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.About converting Excel workbook to CBOR
Converting a .xls file to .cbor lifts the document's content out of its original format into a portable one. An .xls file is a legacy Microsoft Excel workbook in the binary BIFF format, Excel's default from its earliest releases through Excel 2003. Each sheet is a stream of typed binary records (cells, formulas, formats) rather than anything textual.
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. For this route the practical draw is an actual IETF standard with a stable, versioned specification and tags express types JSON cannot, without breaking decoders that ignore them, balanced against tag semantics are only as portable as the two ends' agreement on them, which is worth knowing before you commit a large batch.
Why convert XLS to CBOR?
The practical trigger for this conversion is usually a mismatch: with .xls, the 65,536-row ceiling truncates modern datasets. Switching to .cbor buys you an actual IETF standard with a stable, versioned specification, which is why it is the better fit for WebAuthn and FIDO2 attestation and assertion payloads. Because the conversion runs locally, trying it costs nothing but a few seconds of compute on your own machine.
XLS vs CBOR at a glance
| Aspect | Excel workbook (.xls) | CBOR (.cbor) |
|---|---|---|
| Format type | Text-based: characters and structure, so there is no visual quality loss | Lossless: every pixel or sample is preserved exactly |
| How it stores data | composed of typed binary records (id, length, payload), LABELSST for shared-string cells, FORMULA for calculations, and hundreds more | 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 |
| Strongest at | reading exports from ERP, banking, and lab systems that still emit .xls | WebAuthn and FIDO2 attestation and assertion payloads |
| Weak spot | the 65,536-row ceiling truncates modern datasets | tag semantics are only as portable as the two ends' agreement on them |
| Metadata | SummaryInformation streams in the compound file record author, company, and creation and modification timestamps | semantic tags are read and reported; JSON and YAML targets receive their normalized textual form, since neither has a tag mechanism |
Pick CBOR as the output
Select .cbor in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if CBOR is selectable, the route is real and validated.
Convert on your device
Press Convert. A reader for that file's own format opens it in memory on your device and takes out the text and tables; nothing is uploaded.
Verify and download
Each result is checked before the download unlocks: where CBOR has a signature or a structure this converter can read back, the file is re-opened and parsed, and where it has neither, the check is that a non-empty file of the declared type came back. A result that fails is reported as an error instead of being offered for download, and outputs keep the original filename with the .cbor extension.
XLS to CBOR questions, answered
Will converting XLS to CBOR lose quality?
There is no visual quality to lose, because xls is text-oriented and cbor is lossless-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.
Is it private to convert XLS files here?
Yes. The .xls file is processed inside your browser tab and never uploaded. A reader for that file's own format opens it in memory on your device and takes out the text and tables; nothing is uploaded. Close the tab and the file is gone from memory.
Where will the CBOR file work?
Libraries are widely available for C, Rust, Go, Python, Java, JavaScript and .NET, and browsers speak CBOR indirectly through the WebAuthn API. Novus Convert normalizes .cbor locally into a JSON-compatible model and writes JSON, CSV, XLSX, YAML or YML. Tagged values that JSON cannot represent are converted to a documented textual form rather than being silently discarded.
Will the CBOR file be bigger or smaller than my XLS?
It depends on the content: 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. Convert one representative file first and compare before batch-processing a large set.
What happens to the metadata in my XLS file?
In .xls, SummaryInformation streams in the compound file record author, company, and creation and modification timestamps. 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.