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XLSX → JSON
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Fast, secure XLSX to JSON conversion. No registration required.
XLSX is Excel's Office Open XML workbook format, replacing the older .xls binary. Reaching a JSON from there is one hop. A XLSX to JSON conversion lets you reuse the file in a different workflow. JSON Data is easier to share or edit than Excel Spreadsheet for most destinations, and the round trip preserves the important content. Upload above to start; advanced options cover resolution, quality and metadata. One more beat. XLSX is Excel's Office Open XML workbook format, replacing the older .xls binary. Receiving format: JSON is a document format oriented around a particular office suite or publishing pipeline.
Excel Spreadsheet
Source formatXLSX is the modern Microsoft Excel format based on Open XML. It is the industry standard for spreadsheets, supporting formulas, charts, pivot tables, and conditional formatting.
JSON Data
Target formatJSON (JavaScript Object Notation) is a lightweight data interchange format that is human-readable and easy for machines to parse and generate. It has become the dominant format for web APIs, configuration files, and structured data exchange.
Why convert XLSX to JSON
Sending XLSX to someone who expects JSON regularly leads to errors or quality loss as the receiving software performs its own silent re-encode. Converting upstream lets you control the quality trade-offs rather than leaving them to an external tool.
HOW TO CONVERT
XLSX → JSON
Provide the file
Drag and drop or select a XLSX file up to 25 MB. No account required on the free tier.
Run the conversion
We pick the right backend for this pair automatically and produce a JSON that matches the source data exactly.
Retrieve the output
A download link appears as soon as the JSON is ready. For batch jobs, you get a single ZIP download.
Common Use Cases
Share across platforms
Send JSON files to anyone without worrying about whether they have the right software for XLSX.
Embed in documents
Drop JSON output into Word, Google Docs, PowerPoint, Notion or a website without conversion warnings.
Optimize size
JSON often produces smaller files than XLSX for web, email and storage.
Archive & future-proof
Store in a widely-supported format that will still open on future operating systems without legacy plugins.
XLSX vs JSON — Strengths and limitations
What each format does best, and where it falls short.
XLSX Strengths
- Much smaller than legacy .xls files thanks to ZIP + XML.
- Human-readable structure — easy to extract data programmatically.
- Supports macros (as .xlsm variant), charts, pivot tables, conditional formatting.
- Universal support: Excel, LibreOffice, Google Sheets, Numbers, pandas.
- ISO/IEC 29500 standardized.
Limitations
- Macros in .xlsm are a common malware vector — disabled by default in Office.
- 1M-row limit is a cultural problem — people put too much data in Excel.
- Subtle formula differences between Excel, LibreOffice, and Sheets.
JSON Strengths
- Dead-simple — you can memorize the entire grammar on one page.
- Native parsers in every programming language.
- Human-readable and easy to debug.
- Compact — much smaller than equivalent XML.
- Frozen spec — a JSON parser written in 2010 still handles new JSON files from 2026.
Limitations
- No comments allowed — config files feel verbose.
- No trailing commas — a constant source of parse errors.
- No native date, decimal, or binary types — everything is strings or numbers.
XLSX vs JSON — Technical specifications
Side-by-side comparison of the technical details.
XLSX
- MIME type
- application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
- Container
- ZIP (Office Open XML)
- Max rows
- 1,048,576
- Max columns
- 16,384
- Released in
- Microsoft Office 2007
- Variants
- .xlsx, .xlsm (macros), .xlsb (binary)
JSON
- MIME type
- application/json
- Extension
- .json
- Standard
- ECMA-404, RFC 8259
- Encoding
- UTF-8, UTF-16, or UTF-32
- Allowed types
- object, array, string, number, boolean, null
| Specification | XLSX | JSON |
|---|---|---|
| MIME type | application/vnd.openxmlformats-officedocument.spreadsheetml.sheet | application/json |
| Container | ZIP (Office Open XML) | — |
| Max rows | 1,048,576 | — |
| Max columns | 16,384 | — |
| Released in | Microsoft Office 2007 | — |
| Variants | .xlsx, .xlsm (macros), .xlsb (binary) | — |
| Extension | — | .json |
| Standard | — | ECMA-404, RFC 8259 |
| Encoding | — | UTF-8, UTF-16, or UTF-32 |
| Allowed types | — | object, array, string, number, boolean, null |
XLSX vs JSON — Typical file sizes
Approximate file sizes for common scenarios.
XLSX
- Small budget spreadsheet 20–80 KB
- Financial model with charts 1–10 MB
- Large dataset (100k rows) 10–50 MB
- Enterprise model (1M+ rows) 100–500 MB
JSON
- Small config < 1 KB
- REST API payload 1-100 KB
- Database export 10 MB - 100 GB
Quality & Compatibility
Fidelity depends on how close the two formats sit conceptually. Same-family conversions (document↔document, audio↔audio) keep the essentials intact. Cross-family jobs (image→video, text→PDF) reinterpret the source into a genuinely different artefact, so expect the JSON to emphasise different attributes than the XLSX.
Tips for Best Results
- If the XLSX contains sensitive data, strip metadata in the JSON export (toggle under Advanced) before sharing publicly.
- Conversion settings that look obscure (bitrate, colour profile, compression level) matter mostly for archival and professional workflows — defaults are fine for everyday use.
- Batch conversions share settings across every file in the job; set them once, apply to many.
Frequently Asked Questions
Yes. The free tier accepts files up to 25 MB without registration, email capture or watermarks; paid plans go up to 2 GB. Paid plans raise the size cap, enable batch conversions and provide a REST API for automation, but nothing on the free tier is quality-limited — the output is exactly the same as on any paid plan.
Uploads run over HTTPS, files are processed in isolated containers, and both the source XLSX and the JSON output are auto-deleted within two hours. No account is required, file contents are never logged, and KaijuConverter does not use uploads for AI training. The paid plan adds a signable data-processing agreement for regulated workflows.
Most files finish in well under a minute. Small images and documents are typically ready in a few seconds; large video or audio files scale roughly with duration. Upload speed from your network is usually the dominant factor, not server time.
Related comparisons
See these formats side by side to understand which fits your use case best.
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Read guideSecure & Private Conversion
Your files are encrypted during transfer, processed in isolated containers, and automatically deleted within 60 minutes. We never read, share, or store your data.