Excel to JSON Converter

About this tool

XLSX to JSON converts Excel workbooks (.xlsx, .xls) into a JSON array that any modern API or database can consume. Upload a workbook, pick which sheet to convert, choose whether the first row is a header (used as object keys) or whether to auto-name columns col1, col2, …, and decide on type handling. With Coerce numbers & booleans on (the default), the tool reads the text each cell displays and turns plain integers, decimals and lowercase true/false into JSON numbers and booleans, so "42" becomes 42; Excel TRUE/FALSE cells and formatted numbers like 1,234.50 stay strings. With it off, you get Excel's own cell values: numbers, booleans, text and dates as serial numbers. The tool uses SheetJS, loaded from cdnjs when you pick a file. The conversion runs in your browser via the File API — your spreadsheet never reaches a remote server. Output JSON is pretty-printed and can be copied or downloaded as a .json file.

Why use it

• Browser-Only Privacy: Files are parsed in your tab via the File API and SheetJS — Excel data with customer records, salaries, or financial details never reaches a remote server.

• Multi-Sheet Workbooks: Every sheet in the workbook is available in the picker, so you can convert each sheet on demand without splitting the file beforehand.

• Header Row Option: Choose between using row 1 as object keys (the standard "first row is header" convention) or treating all rows as data with auto-generated column names.

• Two Type Modes: Coercion turns displayed numbers and lowercase true/false into JSON types; switching it off returns Excel's native numbers, booleans and date serials instead.

• Native Excel Format Support: SheetJS handles both .xlsx (OOXML) and legacy .xls (BIFF) binary formats — no need to convert files first in Excel.

• Direct Download: Save the JSON output as a file with the original workbook name and sheet name embedded, ready to commit or send to teammates.

How to use

1. Click the Upload XLSX or XLS file button and pick a workbook from your device.
2. Once parsed, choose which sheet to convert from the dropdown — multi-sheet workbooks all become available.
3. Pick header mode: First row is header to use row 1 as object keys, or No header to auto-name columns col1, col2, ….
4. Leave Coerce numbers & booleans on to parse displayed text like 42 or true into JSON types, or turn it off to keep Excel's own cell types.
5. Click Convert to produce the JSON array and review it in the output panel.
6. Copy the JSON to clipboard or click Download .json to save it to disk.

When it helps

• Migrating data from a customer-supplied Excel sheet into a Node.js, Python, or REST API pipeline that expects JSON.
• Generating fixtures for application tests from a hand-edited Excel file maintained by non-developers.
• Producing seed data for a database from a spreadsheet that finance or operations teams update weekly.
• Converting a single sheet of a multi-sheet Excel report into JSON for visualisation in a dashboard.
• Pre-processing Excel exports from legacy ERP systems before importing into a modern SaaS API.
• Quickly inspecting the structure of an unfamiliar Excel file by viewing it as JSON in the browser.

Examples

Excel sheet:
| id | name  | score |
|----|-------|-------|
| 1  | Alice | 9.5   |
| 2  | Bob   | 7     |

[
  {
    "id": 1,
    "name": "Alice",
    "score": 9.5
  },
  {
    "id": 2,
    "name": "Bob",
    "score": 7
  }
]

Excel sheet:
| Alice | 30 |
| Bob   | 28 |

[
  {
    "col1": "Alice",
    "col2": 30
  },
  {
    "col1": "Bob",
    "col2": 28
  }
]

Excel sheet (zip typed as text, qty a number, active a TRUE cell):
| zip   | qty | active |
| 01234 | 5   | TRUE   |

[
  {
    "zip": "01234",
    "qty": 5,
    "active": true
  }
]

Tips

• Coerce numbers & booleans is on by default — turn it off when string-formatted values like ZIP codes or phone numbers must keep their leading zeros.
• If your Excel file has a multi-row header (e.g. category + subcategory), pre-merge it to a single header row in Excel first; the tool only treats one row as header.
• For very large workbooks (>50 MB), browser memory becomes the limit — split into smaller files or use a server-side parser like Python's openpyxl.
• The download is named <workbook>-<sheet>.json using the sheet name as-is, so rename the file if the sheet name contains spaces or symbols.
• With coercion on, dates appear as the date text Excel shows; with it off they appear as serial numbers — pick the mode that suits your downstream code.

Frequently Asked Questions

Glossary

XLSX

The modern Excel file format, based on Office Open XML (OOXML) packaged in a ZIP archive. Standard since Excel 2007 and the default for new workbooks.

XLS

The legacy Excel binary format (BIFF), used by Excel 97-2003. Still common in enterprise software exports — handled by this tool through SheetJS.

SheetJS

An industry-standard JavaScript library for reading and writing spreadsheet formats including XLSX, XLS, CSV, and ODS. Loaded from CDN only when a file is selected.

Header row

The first row of a sheet, conventionally containing column names. When enabled, those names become object keys in the JSON output.

Type coercion

Converting string values that look like numbers or booleans into their native JSON types. Optional — disable when values must keep their original string form (e.g. ZIP codes with leading zeros).

Sheet

One tab within an Excel workbook. Workbooks can contain many sheets; this tool converts one sheet at a time and shows them all in a picker dropdown.