Free DICOM Viewer
DICOM Viewer opens DICOM files, folders and ZIP archives in your browser, groups them into studies and series and displays CT, MR, X-ray and ultrasound images with window/level presets, zoom, cine and measurements in millimeters and Hounsfield units. It reconstructs coronal and sagittal views, lists every tag and anonymizes files before sharing. Not for diagnosis.
- Compression:
- RLE, JPEG, JPEG-LS, JPEG 2000
- Views:
- Axial, coronal, sagittal (MPR)
- Anonymization:
- DICOM PS3.15 basic profile subset
- Price:
- Free
- Runs:
- Locally, in your browser
- Uploads:
- None: files never leave your device
- Account:
- Not needed
Quick answers
Are my medical images uploaded anywhere?
No. Files are read and decoded by your browser on your own device, also for anonymization and export. Nothing is sent to a server, and closing the tab discards everything.
Can I use this viewer for diagnosis?
No. It is not a medical device and has not been validated for clinical use. Use it to look at your own images, for teaching, research or to check files, and rely on certified software and your doctor for diagnosis.
Processed on your device: your files are never uploaded. How it works
Network activity in this tab
What this page has requested since you opened the site in this tab. An upload is any request that sends data: POST, PUT, PATCH or a request with a body.
No uploads: nothing has been sent from this page.
No network requests yet.
To see every request, open your browser's developer tools (Network tab).
How to use the DICOM Viewer
- Drop DICOM files, a whole folder or a ZIP archive (or use Open a folder). Files without extension and files without the DICOM preamble work too. Nothing is uploaded.
- Pick a series on the left. Scroll through slices with the mouse wheel, the arrow keys or the slider, or press Play for cine loops.
- Adjust brightness and contrast with right-drag, a CT preset or the center/width boxes; zoom, pan, rotate, flip and invert from the toolbar or the keyboard.
- Measure lengths, angles and regions (mean, SD, min/max in HU for CT, area), open the MPR tab for coronal and sagittal reconstructions, or browse every tag in the Tags tab.
- Save the view as PNG or JPG, or anonymize the series and download clean DICOM files as a ZIP.
Credits & open source
Our own code plus open-source libraries. Thank you to the people who make these projects.
- dicomParserParses DICOM Part 10 files and their data elements. © Chris Hafey and Cornerstone contributors · MIT
- Cornerstone OpenJPEG codecJPEG 2000 decoder compiled to WebAssembly. © Chris Hafey and Cornerstone contributors; wraps OpenJPEG (Université catholique de Louvain and contributors, BSD-2-Clause) · MIT
- Cornerstone CharLS codecJPEG-LS decoder compiled to WebAssembly. © Chris Hafey; wraps CharLS (Team CharLS, BSD-3-Clause) · MIT
- Cornerstone libjpeg-turbo codecBaseline JPEG decoder compiled to WebAssembly. © Chris Hafey and Cornerstone contributors; wraps libjpeg-turbo (IJG, D. R. Commander and contributors; IJG/BSD-3-Clause/zlib) · ISC
- jpeg-lossless-decoder-jsLossless JPEG (ITU-T T.81 process 14) decoder used by DICOM. © RII-UTHSCSA (Research Imaging Institute, UT Health San Antonio) · MIT
- fflateFast ZIP compression for batch downloads. © Arjun Barrett · MIT
Web platform APIs used: Canvas 2D, Web Workers, WebAssembly, File API, Pointer Events, Keyboard Events, Web Crypto.
Full license texts: third-party notices · all credits
Frequently asked questions
Which DICOM files are supported?
Uncompressed images of any bit depth (little and big endian), RLE, JPEG baseline, JPEG Lossless, JPEG-LS and JPEG 2000 compressed images, single and multi-frame, grayscale, RGB, YBR and palette color. 12-bit JPEG, HTJ2K and video (MPEG, H.264) DICOM files can be opened but not displayed; their tags can still be browsed.
How do I open a CD from a hospital?
Copy the CD's content to your computer (or select the drive) and use Open a folder, or drop the folder on the page. The viewer finds the DICOM files inside, also those without extension, and ignores the DICOMDIR index and other files.
Why can't I get the MPR (coronal/sagittal) view?
Reconstruction needs a stack of parallel grayscale slices with position and orientation information, the same size and regular spacing, such as most CT and MR series. Scout images, X-rays, ultrasound loops, series with missing slices or gantry tilt can't be reconstructed.
What does the anonymizer remove?
Names, IDs, birth date, addresses, institution, physicians and operators, accession numbers and other identifying attributes from a subset of the DICOM PS3.15 basic profile, plus every other person name and all private tags. Dates are shifted by the number of days you choose (or removed) and UIDs are regenerated consistently. Text burned into the image pixels is not removed, so check ultrasound and screenshot images before sharing.
Are the measurements accurate?
Distances and areas use the pixel spacing stored in the file. When only the imager (detector) pixel spacing is available, as in many X-rays, values are measured at the detector and are not corrected for magnification. Without spacing, results are given in pixels.