What is the XLT file format?
.xlt is the Microsoft Excel 97-2003 template format - the template counterpart of the binary .xls workbook. Opening an .xlt file in Excel creates a new untitled workbook pre-populated with the template's formatting, formulas, and content, rather than opening the template itself for editing. To modify the template directly, it must be opened via File > Open.
Internally, .xlt uses the OLE2 Compound File Binary (CFB) container - the same D0 CF 11 E0 magic-byte header shared by .xls, .doc, and .ppt. Inside the CFB, a Workbook stream holds BIFF8 records; a workbook-type flag in the BIFF8 globals substream distinguishes a template from an ordinary workbook. .xlt files may also embed a VBA Project stream, enabling macro-capable templates with the same security considerations as macro-enabled .xls files.
The BIFF8 format enforces hard limits: 65,536 rows and 256 columns per worksheet, and a maximum of 255 worksheets per workbook.
.xlt was introduced with Excel 97 and remained the template standard through Excel 2003. Office 2007 replaced it with .xltx (XML-based, no macros) and .xltm (XML-based, macro-enabled). Modern Excel still opens .xlt files but prompts you to save in the current format. LibreOffice Calc, WPS Office, and Apple Numbers can also read .xlt templates.
Security & safety
RISK: MEDIUMXLT files can contain VBA macros, making them a potential malware vector - identical risk to XLS. Never enable macros in an XLT received unexpectedly via email. Excel opens internet-sourced files in Protected View; keep it enabled. For reading the data only, open in Google Sheets or LibreOffice Calc, which do not execute Excel VBA.
Format details
in a nutshellPrograms that open XLT files
Windows4 apps
Microsoft Excel
Paid File > Open to edit the template itself, or double-click to create a new workbook from it. Save As XLTX to upgrade to the modern format. 
LibreOffice Calc
Open-source File > Open to open the XLT template for editing; free alternative with high XLT compatibility. 
SoftMaker FreeOffice (PlanMaker)
Free Opens XLT files in PlanMaker; free tier of SoftMaker's office suite. 
macOS3 apps
Microsoft Excel
Paid File > Open to edit the template, or double-click to create a workbook from it. 
Linux1 app
Google Sheets
Free Upload to Google Drive and open with Google Sheets; imports the sheet structure and data. Technical details
deep spec| Format type | OLE2 CFB container with BIFF8 records (binary spreadsheet template) |
| Magic bytes | `D0 CF 11 E0 A1 B1 1A E1` (OLE2 Compound File Binary header) |
| Byte order | Little-endian |
| Container | OLE2 / Compound File Binary (CFB) - shared with `.xls`, `.doc`, `.ppt` |
| Internal format | BIFF8 (Binary Interchange File Format 8) record stream |
| Template identifier | Workbook type flag in BIFF8 globals substream distinguishes template from workbook |
| Compression | None (uncompressed binary records inside CFB) |
| Encryption | Optional RC4 or XOR legacy encryption |
| Row/column limit | 65,536 rows × 256 columns per worksheet (BIFF8 hard limit) |
| Worksheet limit | 255 worksheets per workbook |
| Macro support | Yes - optional embedded VBA Project stream in the CFB container |
| Superseded by | XLTX (XML/ZIP, no macros) and XLTM (XML/ZIP, macro-enabled), both introduced in Office 2007 |
| Released | 1997 (Microsoft Excel 97, as the template variant of BIFF8) |
| Latest version | BIFF8 (Excel 97-2003); superseded by XLTX/XLTM (2007) |
| Specification | learn.microsoft.com |
XLT conversions
Community Q&A
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