Excel to JSON Converter

Convert Excel to JSON

This tool transforms Excel spreadsheet data into JSON format, making it easy to use your tabular data in web applications, APIs, and databases. The conversion runs entirely in your browser — no data is uploaded to any server.

How to Use

1. Upload a file — Click the upload area and select an Excel file (.xlsx, .xls, .csv)
2. Or paste data — Copy cells from Excel and paste into the text area
3. Get JSON — Your data is instantly converted to JSON format
4. Copy or download — Use the buttons to copy to clipboard or download as .json

Supported Formats

How Data is Converted

The first row of your spreadsheet becomes the JSON property names (keys), and each subsequent row becomes an object in the output array:

Excel input

| name  | age | city     |
|-------|-----|----------|
| Alice | 30  | New York |
| Bob   | 25  | Boston   |

JSON output

[
  { "name": "Alice", "age": 30, "city": "New York" },
  { "name": "Bob", "age": 25, "city": "Boston" }
]

Data Type Detection

The converter automatically detects and preserves data types:

• Numbers — Numeric cells become JSON numbers
• Booleans — "true"/"false" become JSON booleans
• Text — Everything else becomes JSON strings
• Empty cells — Become empty strings

Copy-Paste from Excel

The fastest way to convert small datasets: select cells in Excel, press Ctrl+C (Cmd+C on Mac), then paste directly into the text area. Excel uses tab characters as delimiters when copying, which this tool handles automatically.

Privacy & Security

Your data never leaves your computer. The entire conversion process runs in your web browser using JavaScript. No files are uploaded to any server, making this safe for sensitive or confidential data.

Programmatic Conversion

JavaScript (with SheetJS)

import * as XLSX from 'xlsx';

const file = await fetch('data.xlsx');
const buffer = await file.arrayBuffer();
const workbook = XLSX.read(buffer);
const sheet = workbook.Sheets[workbook.SheetNames[0]];
const json = XLSX.utils.sheet_to_json(sheet);
console.log(JSON.stringify(json, null, 2));

Python (with pandas)

import pandas as pd
import json

df = pd.read_excel('data.xlsx')
json_data = df.to_json(orient='records')
print(json.dumps(json.loads(json_data), indent=2))

Common Use Cases

• API development — Convert sample data to JSON for testing
• Database seeding — Transform spreadsheet data for database imports
• Web applications — Use spreadsheet data in JavaScript apps
• Data migration — Convert legacy Excel data to modern formats
• Configuration files — Transform spreadsheet configs to JSON

Related Tools

• JSON to Excel — Convert JSON back to Excel format
• CSV to JSON — Convert CSV files to JSON
• JSON Validator — Validate your JSON output
• JSON to Table — View JSON as a table

Frequently Asked Questions

Is my data secure?

Yes. All processing happens in your browser. Your Excel file is never uploaded to any server. You can verify this by using the tool offline or checking your browser's network tab.

What's the maximum file size?

Since processing happens in your browser, the limit depends on your device's memory. Most modern browsers handle files up to 50MB without issues. For very large files, consider using a programming library.

Can I convert multiple sheets?

Currently, the tool converts the first sheet only. For multi-sheet workbooks, export each sheet separately or use a programming library for full control.

Why are my numbers becoming strings?

Ensure your Excel cells are formatted as numbers, not text. If cells contain leading zeros (like zip codes), they may be stored as text intentionally.

Can I convert .xlsx files?

For best results with .xlsx files, save your spreadsheet as .csv or .xls (Excel 97-2003 format) first. Alternatively, copy the data directly from Excel and paste it into the text area.

Common Mistakes & Pro Tips

• Dates often arrive as serial numbers, not dates — Excel stores dates internally as a number of days since 1899-12-30 (the 1900 date system), so a cell showing 2024-03-01 may convert to 45352. Use a converter that reads the cell's number format to emit an ISO date string, or convert serials yourself with the 1899-12-30 epoch.
• A workbook has multiple sheets — pick the right one — An .xlsx file can contain many worksheets, and most converters default to the first sheet only. If your data is on "Sheet2" or a named tab, select it explicitly, or you'll silently convert the wrong (or an empty) sheet.
• Merged cells leave blanks behind — When cells are merged, the value lives only in the top-left cell and the rest of the merged range reads as empty. This commonly turns grouped headers or category labels into nulls on every row except the first, so flatten/unmerge or forward-fill those columns before relying on them.
• Leading zeros vanish when stored as numbers — If a column like ZIP code or SKU was typed as a number in Excel, 01234 is stored as 1234 and the zero is gone before you ever export. The only fix is at the source: format those columns as Text in Excel so the original digits are preserved.
• The displayed value can differ from the stored value — Excel shows formatted/rounded values (a cell may display 3.14 while storing 3.14159265) and formula cells display a result while storing the formula. Decide whether you want the cached computed value or the raw stored number, since these can differ by many decimal places.