LTD File

What are LTD files and how to open them

Are you having problems opening a LTD file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your LTD files.

What is a LTD file?

A .LTD file is a LogTag Data file.

LogTag Data files with extension .ltd store recorded measurements from LogTag® temperature (or temperature/humidity) data loggers. These files are downloaded from the physical LogTag device into the LogTag Analyzer software and hold all of the logger's recorded readings in an encrypted, non-editable form. They serve as the primary archive format in LogTag's workflow - ideal for compliance ‎and audit-grade record-keeping.

The legacy .ltd format was the main file format used by LogTag Analyzer prior to version 3.0 and remains supported in newer versions. It fully preserves all measurement data and metadata such as device ID, start/stop timestamps, and recorded logging intervals. It does not include optional visual or user-interface settings like annotations, zoom level, chart settings or receiver notes; those appear only in the newer .ltdx (LogTag Data Extended) version. When saving or sharing data with users running older versions of Analyzer, .ltd format can be chosen to ensure compatibility. All core recorded readings in .ltd files are preserved even when saved from newer software.

The .ltd file is proprietary, secured and tamper-proof. It can only be opened by LogTag Analyzer; it cannot be edited to alter readings or overwrite prior data. To share data with others or use in tools like spreadsheets or reports, exports to formats such as CSV or PDF are provided, but those exports lose the tamper-proof guarantees.

Each .ltd file begins with a fixed ASCII signature at its start: the header contains the text "LogTagProductDataFile" followed by a line feed and a 0x1A byte at offset 0.

How to open LTD files

We have identified one LTD opener that is compatible with this specific type of LTD file.

Programs that open LogTag Data files

Last updated: August 7, 2026

Various apps that use files with this extension

These apps are known to open certain types of LTD files. Remember, different programs may use LTD files for different purposes, so you may need to try out a few of them to be able to open your specific file.

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