What is a .PT file?
A .pt saved by PyTorch 1.6 or later is a ZIP holding a Python pickle and the raw tensor data it points at, while older checkpoints are a bare pickle stream. The pickle describes how to rebuild the saved object, which is convenient and is also why loading one is not a safe operation.
- Did you know
- A pickle is a program, not a document: it can name any Python function at all, and unpickling calls it - which is exactly the problem Safetensors was created to solve.
- Analyser handles .PT alongside related formats such as .ONNX, .Safetensors, .GGUF and more.
- In Analyser's format library, .PT sits in the System & disk category.
- What Analyser shows you
- Open machine-learning models and read what is actually in them. ONNX models and frozen TensorFlow graphs are drawn as a graph: every operation as a box, every tensor flowing between them as a line, laid out left to right by depth so parallel branches sit side by side. Neither format stores the connections - a node follows another because one of its inputs is one of the other's outputs - so the edges are recovered by matching those names. Alongside the picture: the operation mix that fingerprints the architecture, the input and output shapes (including the dynamic ones a model leaves open), every weight tensor with its shape, and the total parameter count. Weight files are read too - Safetensors and GGUF give up their full tensor list, precision and parameter count, and a GGUF also declares its architecture, context length and quantisation. A PyTorch checkpoint is a Python pickle, which is a program rather than a document, so nothing in it is ever run: the opcodes are read as bytes and every module it would import is listed, with anything a file of numbers has no business touching flagged. Keras models have their layer list read from the architecture JSON.
- Open a .PT file
- Drag a .PT file onto the Analyser home page (or tap to pick one). It opens entirely in your browser - nothing is uploaded, there is no account, and it works offline once installed.