Free online TMP to XLSX converter

Programs create .tmp files as temporary working copies, backups, or autosave data, and some contain spreadsheet content that must be recovered in Excel format. Converting one to .xlsx is possible only when the file contains a recognizable spreadsheet or tabular structure; changing the extension alone does not convert it.

What the TMP format is

.tmp is a generic temporary-file extension, not a single standardized document format. Desktop spreadsheet applications, document editors, database tools, and import utilities may create temporary files while saving, calculating, recovering, or locking a document.

A document-related TMP file may contain an incomplete workbook, a recovery copy, XML or binary spreadsheet data, or plain text arranged in rows and columns. The creating program normally removes it after a successful save, so a remaining file can indicate an interrupted operation or unsaved changes. Its filename and extension rarely identify the internal format reliably.

What the XLSX format is

.xlsx is the Office Open XML spreadsheet format used by Microsoft Excel, LibreOffice Calc, Apple Numbers, and many data-processing applications. It stores worksheets, cell values, formulas, formatting, charts, tables, and workbook metadata in a ZIP-based package of XML files.

XLSX is suitable when the recovered data must be edited, sorted, calculated, shared, or archived as a spreadsheet. It generally preserves structured spreadsheet content more reliably than CSV, including multiple sheets and formulas, but it does not preserve every feature from specialized or damaged source files.

How to actually convert TMP to XLSX

Try the creating application first

1. Make a copy of the TMP file and work on the copy; do not rename or modify the original.
2. Identify the program that created it from the file location, timestamp, neighboring files, or the interrupted task.
3. Open the copy in that program. In Excel, use File → Open → Browse, select All files, and choose the TMP file. If Excel reports that the file is damaged, use File → Open → Open and Repair.
4. In LibreOffice Calc, use File → Open and select the file. If an import dialog appears, choose the correct character encoding, delimiter, and text qualifier.
5. After the contents load, use File → Save As, select Excel 2007–365 (*.xlsx), and save under a new filename.

Import a text-based TMP file

If a text editor shows readable rows separated by commas, tabs, semicolons, or line breaks, open the file with Excel or Calc as delimited text. Set the delimiter explicitly, inspect the column preview, and format identifier columns as Text so values such as leading-zero account numbers are not altered. Then save the imported sheet as .xlsx.

Convert it online

You can upload the file to 101convert.com and convert it for free without installing software. This works only when the service can identify the TMP file's internal structure; a generic or incomplete temporary file may be rejected or produce an incomplete workbook.

Quality and compatibility limits

Do not assume that a TMP file is an XLSX file with the wrong extension. A genuine XLSX package normally begins with the ZIP signature PK, while older Excel workbooks use a different binary format; a text editor may reveal whether the file is readable text instead. Renaming is appropriate only when the file's internal format has already been identified.

Temporary files can be incomplete, locked, encrypted, or missing workbook metadata. Recovery may preserve values while losing formulas, formatting, charts, external links, macros, or multiple worksheets. After saving, check sheet count, formulas, dates, decimal separators, leading zeros, merged cells, and totals against the original source or application recovery view.