How do I open a .NII file on Windows or Mac?

You can open .NII files using 3D Slicer, FSL (FMRIB Software Library), SPM (Statistical Parametric Mapping), ITK-SNAP, Mango Viewer. If you do not have native software installed, you can use OpenAnyFile's free File Identifier or convert .NII to a standard format in your browser.

Is a .NII file safe to open?

This format carries a safety rating of Low Risk. NIfTI files combine spatial affine transform matrices to map brain coordinates precisely

Can I convert a .NII file to other formats?

Yes! .NII can be converted to formats such as .DCM, .PNG directly in your web browser.

What should I do if a .NII file is corrupted or won't open?

If your .NII file displays an invalid header or signature error, check its magic bytes hex header (Varies) using OpenAnyFile's Magic Byte Detector or follow our step-by-step file repair guide.

How do I open .NII files?

You can open .NII files using 3D Slicer, FSL (FMRIB Software Library), SPM (Statistical Parametric Mapping), ITK-SNAP, Mango Viewer.

Medical & Science • MIME: application/octet-stream

.NII – NII File Format

Q: What is a .NII file?

A .NII file is a NII File Format associated with Medical & Science. NII (Neuroimaging Informatics Technology Initiative) is a file format widely used in neuroscience and brain imaging research to store 3D and 4D functional Magnetic Resonance Imaging (fMRI) data.

NII (Neuroimaging Informatics Technology Initiative) is a file format widely used in neuroscience and brain imaging research to store 3D and 4D functional Magnetic Resonance Imaging (fMRI) data.

Primary Category Medical & Science

MIME Type application/octet-stream

Magic Bytes Signature Varies

Security Risk Rating Low Risk

Recommended Software to Open .NII

3D Slicer

windows, mac, linux • Free

FSL (FMRIB Software Library)

windows, mac, linux • Free

SPM (Statistical Parametric Mapping)

windows, mac, linux • Free

ITK-SNAP

windows, mac, linux • Free

Mango Viewer

windows, mac, linux • Free