Choose the smallest useful sheet range
Recalculate and save the XLSX in its source application, then select a visible sheet and a range such as A1:F40. Hidden rows and columns inside that range remain included; hiding a column is not a privacy control. Merged cells, missing formula results and Excel errors stop conversion. Charts and formatting do not become JSON.
Decide whether the first row contains field names
Choose records when the first selected row contains unique, non-empty keys and at least one following row contains data. Choose row arrays for a headerless table or repeated labels. Every Excel value becomes a JSON string and blank cells become empty strings. A displayed rounded number is not a lossless export of its underlying numeric value.
Import consistent flat JSON
Supply records with identical key sets, or arrays of equal-length rows. Nested objects, mixed records and arrays, missing keys and duplicate keys need a deliberate schema change before import. Numbers are read from their original tokens, preserving long integers and spellings such as 1.20e3 as Excel text. Strings beginning with an equals sign remain inert text.
Treat null as a data decision
By default, null values stop the import. If an empty text cell is appropriate, select that option explicitly and review the reported count. The resulting workbook cannot distinguish a converted null from an original empty string. Keep the source JSON if that distinction matters; this tool does not claim a type-preserving round trip.
Review the complete download
The preview is limited to the first 30 rows and 10 columns, or 50,000 JSON characters. Download and inspect the whole accepted result. Check headers, row counts, identifiers, empty values and date text. The browser keeps no file history, so save the output before clearing the workspace or leaving the page.