Excel to JSON moves values, not the whole workbook
A web app or an API needs JSON, and the data is sitting in Excel.
One sheet becomes a list of row objects. Several sheets become one JSON object keyed by sheet name. Empty cells are kept as empty strings. The file stays in the browser.
Dates and extra sheets after Excel to JSON
Formulas become their cached values, not live formulas. Nested JSON cannot represent a merged cell. Check the shape before you post it to an API.
A related step, if you still need one, is JSON to Excel.
When Excel to JSON is the right page
Excel to JSON sits on this site because XLSX and JSON are not interchangeable, even when they look similar in a file list. A web app or an API needs JSON, and the data is sitting in Excel. Spreadsheets, charts, and CSV exports start here for most offices in 2026. Developers convert JSON when a payload must become a sheet, XML, or CSV.
One sheet becomes a list of row objects. Several sheets become one JSON object keyed by sheet name. Empty cells are kept as empty strings. The file stays in the browser.
What you give up by leaving XLSX
XLSX is the current Excel workbook. It can hold more than one sheet, plus formulas and formatting. A conversion aimed at CSV or JSON flattens that richness. Charts and macros are not the point.
Keep the workbook you calculated in. An export is a copy of values.
What you gain, and do not gain, with JSON
The download has to be JSON, because that is the format the next step named. Developers convert JSON when a payload must become a sheet, XML, or CSV. A list of similar objects maps cleanly to rows.
This is not encryption. Do not paste passwords or live tokens.
A test that matches the real file
Start from the question the other software asked. If it asked for JSON, Excel to JSON is the matching page. If it asked for something else, switch tools instead of hoping a similar extension will pass. A web app or an API needs JSON, and the data is sitting in Excel. One sheet becomes a list of row objects. Several sheets become one JSON object keyed by sheet name. Empty cells are kept as empty strings. The file stays in the browser. The limit is the part people skip, and it is the part that decides whether the download is usable. Formulas become their cached values, not live formulas. Nested JSON cannot represent a merged cell. Check the shape before you post it to an API. The file stays in your browser and is not uploaded. The limit is 100 MB. Keep the original until the download has been opened in the program that will use it. Check three things in the download: it opens, the XLSX material you cared about is still there, and the file size or the layout is what the form described. A new extension alone is not those three things. If a portal, a teacher, or a client rejects the file, send them the original XLSX as well when you are allowed to. Excel to JSON is a convenience copy. It is not a new master. Spreadsheets break at quiet places: a second sheet, a date that changed, a leading zero that vanished, a comma inside a name. After Excel to JSON, open the result in a text editor as well as Excel. Excel guesses types and hides the delimiter. The workbook you calculated in is still the master.
Here is the decision for Excel to JSON. You start with XLSX and you stop when a real program accepts JSON. Values, dates, and several sheets can travel when the tool writes a real workbook. Nested lists of unknown length will not become one tidy sheet. If those two sentences describe a tradeoff you do not want, do not convert. Renaming the extension by hand will not do this job. Running the tool twice on its own output will not do it either.
Formulas become their cached values, not live formulas. Nested JSON cannot represent a merged cell. Check the shape before you post it to an API.
A related step, if you still need one, is JSON to Excel.
Other jobs start from the homepage, where each tool is named for the conversion it actually does.