Excel to JSON Converter.

Convert Excel to JSON online — free and private

An Excel to JSON converter turns spreadsheet rows and columns into structured JSON that APIs, databases, and JavaScript can use directly. Drop an .xlsx file above and the tool reads your header row, maps each data row to an object, and shows the JSON instantly. Unlike server-based converters, this one reads the workbook entirely in your browser — so you can convert XLSX to JSON without uploading confidential data.

How to convert Excel to JSON in three steps

1. Drop your file onto the upload area, or click to browse for an .xlsx, .xlsm, or .csv file.
2. Choose your options — which worksheet to convert, the output shape, and whether the first row is a header.
3. Export — copy the JSON or download it as data.json.

Multi-sheet, real dates, and typed numbers

A workbook is more than one table, so this converter lists every worksheet and lets you pick which to convert. It reads the file's style table to turn date-formatted cells into readable ISO dates like 2024-01-15 instead of leaving them as Excel serial numbers — the detail most converters get wrong. Numbers stay numbers and text stays text, so IDs, ZIP codes, and product codes survive intact.

Pick the output shape your code needs

Choose array of objects for the row-keyed shape most APIs expect, 2D array for the raw grid, or keyed by column for a column-oriented object that maps straight onto a pandas DataFrame. CSV files are accepted too, so the same tool covers both spreadsheet formats.

The Excel date problem, explained

This is the one thing that breaks nearly every Excel-to-JSON conversion. Excel does not store dates as dates — it stores them as numbers, counting days since 1 January 1900, and only displays them as dates through cell formatting. So a cell showing 15/01/2024 actually contains 45306.

A converter that reads raw cell values hands you 45306 and you are left reverse-engineering a date system with a famous off-by-one bug (Excel believes 1900 was a leap year — it was not). This tool reads the workbook's style table to identify which cells are date-formatted and converts them properly:

{ "name": "Ada", "joined": 45306 }          ← what naive converters give you
{ "name": "Ada", "joined": "2024-01-15" }   ← what you actually wanted

Convert Excel to JSON in Python or JavaScript

Python (pandas) — sheet_name=None reads every worksheet:

import pandas as pd

df = pd.read_excel("data.xlsx", sheet_name="Sheet1")
df.to_json("data.json", orient="records", indent=2, date_format="iso")

# every sheet at once → dict of DataFrames
sheets = pd.read_excel("data.xlsx", sheet_name=None)

Pass dtype=str if you need to protect leading zeros in IDs and ZIP codes, which pandas will otherwise strip.

JavaScript / Node.js (SheetJS):

import * as XLSX from "xlsx";

const book = XLSX.readFile("data.xlsx", { cellDates: true });   // cellDates!
const sheet = book.Sheets[book.SheetNames[0]];
const rows = XLSX.utils.sheet_to_json(sheet);

Without cellDates: true you get the serial numbers back — the exact problem described above.

Common Excel to JSON problems (and fixes)

“My dates are numbers.” The serial-number issue above. This tool handles it; if you are scripting, set cellDates or date_format="iso".

“My ZIP codes lost their leading zeros.” Something inferred 02134 as the number 2134. Keep those columns as text.

“My .xls file will not load.” The old binary .xls format is not supported. Open it in Excel and re-save as .xlsx.

“I got the wrong sheet.” Workbooks default to the first worksheet. Use the sheet selector to pick the one you want.

“My formulas came through as values.” That is correct and usually what you want — JSON stores data, not formulas. The computed result is what gets exported.

Why use this Excel to JSON tool?

It is fully client-side, with no file-size cap and no upload — a real advantage over tools that send your workbook to a server. Going the other way? Use the JSON to Excel converter, or work with text formats via CSV to JSON and JSON to CSV. Learn more in our guide on how to convert Excel to JSON.