Add your XLSX file
Drop one or more .xlsx 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.
XLSX to BSON
Converting a .xlsx file to .bson 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 XLSX 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 BSON
Converting a .xlsx file to .bson lifts the document's content out of its original format into a portable 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.
A .bson file holds BSON: the binary document format MongoDB stores and transmits. It looks like JSON with types added (every field is length-prefixed and carries a type byte) which makes documents skippable during a scan and gives them an ObjectId, a real date type, and 32- and 64-bit integers distinct from doubles. For this route the practical draw is exact numeric types and native dates, unlike JSON and length prefixes make skipping and partial reads cheap, balanced against often larger than the equivalent JSON, because of length prefixes and field names repeated per document, which is worth knowing before you commit a large batch.
Why convert XLSX to BSON?
The practical trigger for this conversion is usually a mismatch: with .xlsx, date-as-serial-number storage causes subtle off-by-one and timezone bugs. Switching to .bson buys you exact numeric types and native dates, unlike JSON, which is why it is the better fit for inspecting a mongodump export without restoring it to a database. Because the conversion runs locally, trying it costs nothing but a few seconds of compute on your own machine.
XLSX vs BSON at a glance
| Aspect | Excel workbook (.xlsx) | BSON (.bson) |
|---|---|---|
| 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 | xl/worksheets/sheetN.xml holds rows of typed cells; text cells usually point into xl/sharedStrings.xml to avoid repetition | a document is a little-endian int32 total length, a sequence of typed elements, and a terminating null byte |
| Strongest at | the standard vehicle for exchanging spreadsheets between organizations | inspecting a mongodump export without restoring it to a database |
| Weak spot | date-as-serial-number storage causes subtle off-by-one and timezone bugs | often larger than the equivalent JSON, because of length prefixes and field names repeated per document |
| Metadata | 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 | type information is preserved through the conversion summary; JSON, CSV and spreadsheet targets record BSON-specific types as their documented string representations |
Pick BSON as the output
Select .bson in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if BSON 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 BSON 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 .bson extension.
XLSX to BSON questions, answered
Will converting XLSX to BSON lose quality?
There is no visual quality to lose, because xlsx is text-oriented and bson 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 XLSX files here?
Yes. The .xlsx 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 BSON file work?
Official MongoDB drivers for every major language decode BSON, and standalone libraries exist for Python, Java, Go, Rust and JavaScript. Novus Convert decodes .bson in the browser and writes JSON, CSV, XLSX, YAML or YML, handling non-JSON types explicitly: ObjectId and Decimal128 become their canonical string forms and Binary is reported rather than mangled into text.
Will the BSON file be bigger or smaller than my XLSX?
It depends on the content: a document is a little-endian int32 total length, a sequence of typed elements, and a terminating null byte. Convert one representative file first and compare before batch-processing a large set.
What happens to the metadata in my XLSX file?
In .xlsx, 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. 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.
Can I convert BSON back to XLSX?
Yes. The reverse route exists as a separate tool. Bear in mind that round-tripping .xlsx → .bson → .xlsx is not a perfect undo when any lossy step is involved; keep your original if fidelity matters.