Opening a GJF File

The GJF file type is primarily associated with Gaussian.

GJF	File extension: GJF
	File type:	text-based input file

What is a GJF file

GJF files mostly belong to Gaussian. Gaussian Input Files (GJF): These files serve as the primary input for Gaussian computational chemistry software. They are plain text files with a specific structure that the software reads to run quantum chemical calculations. The file typically contains sections for calculation directives, molecular geometry, basis set information, and job settings.
Key components include:

Calculation Directives – instructions that set the type of quantum chemical method.

Molecular Geometry – atomic coordinates and bonding information.

Basis Set Definitions – details required to describe electron distributions.

Job Parameters – settings such as memory limits and convergence criteria.

FilExt.com note: Gaussian processes these instructions to perform tasks like energy computation, structural optimization, and vibrational analysis. For further details, refer to the Gaussian official website.

How can I open a GJF file?

You need a suitable software like Gaussian to open a GJF file. Without proper software you will receive a Windows message "How do you want to open this file?" or "Windows cannot open this file" or a similar Mac/iPhone/Android alert. If you cannot open your GJF file correctly, try to right-click or long-press the file. Then click "Open with" and choose an application. You can also display a GJF file directly in the browser:. Just drag the file onto this browser window and drop it.

Online GJF Text Viewer

Choose your .gjf file to view

or drag and drop it here

Online File Viewer

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How to extract texts from GJF files or capture a screenshot to PDF, JPG, DOCX, TXT, ...

1. To do so, click the "Choose your .gjf file to view" button above.
2. Your GJF file will then be displayed in the browser.
3. Now click on "Save as..." at the top of the page.
4. Then choose the file format (e.g. JPG, PDF, DOCX, TXT, ...) you want.
5. Download the converted file.

GJF file format details:

If you know the file format, you can also find out how to open or edit the file. The file format can be determined based on the file extension and the signature (the first few characters of a file). Nonetheless, different programs can utilize the same file extension to represent distinct file formats. Double-clicking on the file often results in an error when opening. Exact knowledge of the format is therefore important in order to solve problems occurring in files. Our evaluation of the GJF files looks like this:

The file type with the extension 'GJF' is used by a few programs, each with its own file format. The two most common formats are as follows:

• 50% of all GJF files start with the bytes %chk= crucial for this file format. These files are text files and can therefore be read using a text editor. The files are 220 bytes to 5 KB in size, with a median of 1 KB. This file type is based on cutting-edge technology. The files contain the following words: Title Card Required, # hf/3-21g geom=connectivity and Users. Files like these are sometimes connected to system, water, framework, polymorph, structure, graphene, doublet and beta.
• 20% of all GJF files start with the bytes %nproc crucial for this file format. The content consists of readable text data, which can be read using a text editor. Most of these files are 250 bytes to 4 KB in size. Certain words are almost always found in the files, such as nprocshared and freq. These files can be linked to monomer, dipp and scan.

All other GJF files (30%) have different formats, such as mem and Chk. Sometimes used for freq, triplet, dimer or trans. Just click the "Choose your .gjf file to view" button on this page to find out what your GJF file is.