Excel to JSON: free online, fast and secure
Developers and no-code builders often receive data in Excel but need JSON. This converter reads any sheet and outputs an array of objects, using the first row as keys, or an array of arrays if you prefer.
Numbers stay numbers, dates become ISO strings, and you can pretty-print or minify the output before copying or downloading.
How to use Excel to JSON
- Upload Excel. XLSX, XLS, ODS or CSV.
- Choose format. Array of objects or arrays; pretty print on or off.
- Copy or download. Use the JSON in your app.
Why use ConvertKaro Excel to JSON? Free, fast and secure
Many online tools upload your file to a remote server and make you wait. ConvertKaro is different.
100% Free
Use Excel to JSON completely free, every day. No credit card, no “pro” version and no daily cap on files.
Fast results
No waiting for uploads to finish. The work happens on your device the moment you add a file, which makes it noticeably faster than server-based tools.
Secure and private
Your files never leave your device. ConvertKaro does not upload, store or look at your documents and photos, which makes it safe for ID cards, bank statements and private pictures.
No signup, no watermark
You do not need to sign up or log in, and your output is clean, without any logo or branding.
Works on every device
Nothing to install: it runs in any modern browser on phones, tablets and computers.
Typed values
Numbers and booleans come through as real JSON types, not strings.
ConvertKaro vs other online converters
| ConvertKaro | Typical online tool | |
|---|---|---|
| Price | Free forever, every feature | Free trial, then paid plans |
| Your files | Stay on your device | Uploaded to a server |
| Signup | Not needed | Often required |
| Watermark or ads on result | Never | Common on free plans |
| Speed | Instant, no upload wait | Depends on upload speed |
| Daily limits | None | Usually limited |
Common uses for Excel to JSON
- Seeding databases and mock APIs
- Feeding data into React or Vue apps
- Importing into Firebase or Supabase
- Building product catalogues for websites
- Automation tools like Zapier and n8n
Tips for the best results
- Keep header names short and without spaces for clean keys.
- Validate or format with JSON Formatter.
- Go the other way with JSON to Excel.
- Empty cells become empty strings.
Good to know
Office and data files come in many formats. XLSX is Excel’s modern workbook format with sheets and formatting. CSV is plain text with values separated by commas, perfect for imports. JSON and XML are structured formats used by apps and APIs, and Markdown is a simple way to write formatted text. Excel to JSON converts between these formats on your device, so business data such as customer lists, invoices and sales reports never leaves your computer.
| Price | Free, no limits |
|---|---|
| Processing | On your device, no upload |
| Signup | Not required |
| Watermark | None |
| Works on | Android, iPhone, Windows, Mac, Linux |
| Category | Office & data tools |
How Excel to JSON keeps your documents and data files private
Most online converters upload your file to their server, process it there and send it back. That costs time, uses your data pack and means a copy of your file sits on someone else’s computer. Excel to JSON works differently: the page loads the tool into your browser, and your documents and data files are processed by your own phone or computer. The file never travels over the internet, so it cannot be leaked, stored or misused.
Using Excel to JSON on your phone
Excel to JSON is designed for small screens. Buttons are large, options are simple, and downloads save directly to your phone storage. On iPhone, downloaded files appear in the Files app under Downloads; on Android they go to the Downloads folder.
Who uses Excel to JSON?
You do not need any technical knowledge to use it. It is popular with:
- Office staff working with Excel, Word and CSV exports
- Accountants converting reports and statements
- Developers and analysts moving data between systems
- Shop owners exporting orders and product lists
- Students and teachers preparing data for projects
Supported input: XLSX, XLS, ODS, CSV, TSV, DOCX, JSON, XML, YAML, Markdown and HTML.
Frequently asked questions
Which row becomes the keys?
The first row of the sheet.
Can I choose a sheet?
Yes. Select it from the Sheet dropdown.
Are dates converted?
Yes, to YYYY-MM-DD strings.
Is Excel to JSON really free?
Yes. Excel to JSON on ConvertKaro is 100% free with no limits, no signup and no watermark. There is no paid version.
Is it safe to use Excel to JSON online?
It is one of the safest ways to do it, because nothing is uploaded. All processing happens locally on your device, and the files disappear when you close the page.
Does Excel to JSON work on mobile?
Yes. It works in Chrome and Safari on Android phones and iPhones, as well as on tablets and computers. No app is needed.
Is there a file size limit in Excel to JSON?
No upload means no server limit. The only limit is your device’s memory, which comfortably handles everyday files and even large batches.
Will ConvertKaro add a watermark or ask me to sign up?
No. There is no watermark, no login and no email required. Your downloaded file is exactly your result.
Does Excel to JSON work offline?
Once this page has finished loading, the tool keeps working even if your internet connection drops, because all processing happens on your device.
Related free tools
Explore more free tools that work the same way, privately in your browser: JSON to Excel, CSV to JSON, JSON Formatter, Excel to CSV, JSON to CSV.