NII File — Open & Convert .nii Online
What Is a .nii File?
NII (.nii) is a medical file format. NIfTI neuroimaging format for brain scans. Created by NIH, this format is essential for radiologists and clinicians.
How to Open .nii Files
Upload your .nii file to OpenAnyFile and instantly view and reconstruct it in your browser. No software installation required. Works on Windows, macOS, Linux, iPhone, and Android.
Everything About NII Files
Popular NII Conversions
Frequently Asked Questions
What is a .nii file?
A .nii file is a medical format called NII. NIfTI neuroimaging format for brain scans.
How do I open a .nii file without installing software?
Upload your .nii file to OpenAnyFile. Our browser-based tool instantly detects and displays it — no downloads needed.
What program creates .nii files?
.nii files are typically created by NIH.
Can I convert .nii to another format?
Yes. OpenAnyFile converts .nii to PNG, DICOM.
Is it safe to open .nii files online?
Yes. OpenAnyFile processes files in a secure, isolated environment. Files are automatically deleted and all transfers use HTTPS.
Can I open .nii on my phone?
Yes. OpenAnyFile works on all mobile browsers including iPhone and Android.