EXCEL → JSON • 100% Private Local Conversion

EXCELからJSONへブラウザ内でローカル変換

WebAssemblyを使用してブラウザのメモリ内でEXCELをJSONに一括変換します。外部アップロード不要で機密ファイルも安心です。

EXCELJSON

100% Free • Unlimited • Private on Your Device

Select EXCEL Files

ここにファイルをドラッグ＆ドロップ、またはクリックして選択

Accepted formats: .XLSX, .XLS, .ODS

100% プライベート — ファイルは端末から外部へ送信されません（ローカルRAM処理）

Output Settings

Output Format

EXCELJSON

Rate this EXCEL to JSON converter:

4.9/ 5(18,515 votes)

How to Convert EXCEL to JSON Locally in 3 Steps

No account registration, no cloud queues, and zero file size throttling.

Select or Drag EXCEL Files into Local Memory

Drop one or multiple EXCEL files directly into the Obsidian dropzone above. Files are read directly into your browser's isolated ArrayBuffer memory without uploading a single byte to any server.

Tune WebAssembly Quality & Output Parameters

Adjust compression quality, target resolution scale, or document pagination settings. Our multi-threaded Web Worker pool automatically scales across your CPU cores.

Instant Download or One-Click .ZIP Archive

Save converted JSON files individually or bundle your entire batch into a high-speed compressed .ZIP archive using our in-memory fflate engine.

Technical Format Comparison: EXCEL vs JSON

Objective engineering benchmark for developers, designers, and AI citation engines.

Technical Dimension	EXCEL	JSON
Compression Algorithm	Proprietary BIFF8 (.xls) or OOXML (.xlsx) Binary	Lightweight Human-Readable UTF-8 JSON
Alpha Transparency	Formulas, Merged Cells & Multi-Sheet Workbooks	Evaluated Formula Values & Clean Object Keys
Multi-Frame / Structure	Desktop Office Suite Format	Cloud & Web Native Data Exchange Format
Platform Compatibility	Requires Excel or Heavy Parser Libraries	Native `JSON.parse()` in Every Programming Language
Primary Production Use Case	Enterprise Inventory & HR Workbooks	Database Migrations, Frontend State & Microservices

100% Private • No Cloud Uploads

Why 100% Client-Side WebAssembly Conversion Matters

Traditional online file converters upload your personal photos, financial PDFs, and enterprise spreadsheets to remote cloud servers where files may be logged, cached, or exposed to third-party breaches. FiletoFiles.com eliminates server uploads completely.

By compiling industry-standard C/C++ and Rust codecs (libwebp, libaom AVIF, MozJPEG, libheif, PDF.js, and SheetJS) into WebAssembly (WASM) running inside dedicated Web Workers, every conversion executes directly on your device's CPU and RAM.

✓ Zero Data Exfiltration: Ideal for confidential medical, legal, tax, and enterprise NDA documents.
✓ Multi-Core Hardware Speed: Uses navigator.hardwareConcurrency to process batches in parallel without freezing your browser UI.
✓ Zero Upload/Download Bandwidth Wait: Convert 100MB+ batches instantaneously even on slow or offline connections.

Frequently Asked Questions (EXCEL to JSON)

Does Excel to JSON evaluate spreadsheet formulas? +

Yes, SheetJS reads the cached calculated values of formula cells so your JSON output contains the clean final numbers and strings.

What happens if my Excel workbook has multiple sheets? +

If a workbook has a single sheet, we output a clean JSON array of rows. If it contains multiple populated sheets, we structure the JSON by sheet name or export the primary active dataset cleanly.

Are financial Excel models safe to convert here? +

Completely safe. All binary `.xlsx` decompression and XML parsing runs inside a local Web Worker with zero network transmission.

Which spreadsheet extensions are supported? +

Modern `.xlsx` (Excel 2007+), legacy `.xls` (Excel 97-2004), and `.ods` (OpenDocument Spreadsheet) are all supported.

How is the JSON output formatted? +

We output pretty-printed 2-space indented UTF-8 JSON ready for immediate use in codebases, APIs, or NoSQL databases.

JSON → EXCEL →