MAT File Viewer | Open MATLAB .mat Files Online

MAT file viewer that opens MATLAB .mat files without MATLAB. Browse variables, structs and cell arrays, then export to CSV or JSON. Reads v4, v6 and v7 files.

Also known as: mat file viewer · mat file viewer online · open mat file online · open mat file without matlab · mat file to csv · mat to csv converter online · matlab mat file reader · mat file to json · view mat file contents

csv and spreadsheet tools

file converters

viewers

MAT-File Input

Drop a .mat file here, or click to browse

Reads MATLAB v4, v6 and compressed v7 files in your browser with no MATLAB, no Python and no upload.

Workspace

The file's variables will appear here like MATLAB's workspace: name, size and class, with tables for matrices, the fields of structs and the contents of cell arrays.

About MAT File Viewer

A MAT file viewer opens MATLAB .mat files without MATLAB, so you can see what a colleague, an instrument or a course saved. Drop in a file and browse it like MATLAB's workspace: each variable's name, size and class, matrices as tables, struct fields, cell array contents and sparse matrices. Any matrix, char array or struct array exports to CSV for Excel, and any variable to JSON.

Key Features

Reads Level 5 MAT-files from save -v6 and the compressed save -v7 default, plus Level 4 files, in little- and big-endian byte order
Decodes double, single, int8 to int64, uint8 to uint64, logical, char, complex, cell, struct, struct arrays, objects and sparse matrices
Drills into nested structs and cell arrays and shows the MATLAB expression for each value, such as station.name or months{3}
Pages through 3-D and higher arrays one 2-D slice at a time
Exports the selected matrix, char array, cell or struct array to CSV, sparse matrices as row, col, value triplets, and any variable to JSON
Prints a whos-style summary with each variable's size, bytes and class, and reports damaged variables instead of failing the whole file

Use Cases

Opening a .mat dataset from a university course or a Kaggle download on a laptop with no MATLAB license
Converting a MATLAB results matrix to CSV for Excel or Google Sheets
Checking the field names and sizes in a .mat file before writing scipy.io.loadmat code to read it
Looking at sensor or lab instrument exports saved as MAT-files by LabVIEW or a data acquisition system
Turning a MATLAB struct of settings into JSON for a Python or JavaScript project

Supported Formats

MAT-file v7 (compressed)

MAT-file v6

MAT-file v4

CSV export

JSON export

Related Keywords

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How do I open a .mat file without MATLAB?

Drop it here to browse every variable and export matrices to CSV, with nothing to install. In Python, scipy.io.loadmat('file.mat') returns a dictionary of NumPy arrays for v4 to v7 files. GNU Octave, the free MATLAB clone, opens them with load('file.mat'). Files saved with -v7.3 are HDF5 containers instead: open those with h5py or the mat73 package in Python, or ask whoever made the file to re-save it with save('file.mat', '-v7').

Is my data uploaded?

No. The file is decompressed and read in your browser, so research data, grades and proprietary measurements stay on your machine.

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Frequently asked questions

What is MAT File Viewer used for?

MAT file viewer that opens MATLAB .mat files without MATLAB. Browse variables, structs and cell arrays, then export to CSV or JSON. Reads v4, v6 and v7 files.

Is MAT File Viewer free to use?

Yes. MAT File Viewer is completely free with no usage limits, and there is no paid tier required to use it.

Do I need an account to use MAT File Viewer?

No. MAT File Viewer works immediately in your browser with no signup, login, or email address required.

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