Source: https://openmyscan.com/en/guides/how-to-open-dcm-files Guide G–04 · Opening # How to open .dcm files A .dcm file is a [DICOM file](https://openmyscan.com/en/guides/what-is-dicom-format) that may contain one image, multiple frames, or another type of DICOM object. Most people get them in a folder full of similar files (IM00001.dcm, IM00002.dcm, …) from a [hospital CD](https://openmyscan.com/en/guides/hospital-gave-me-scan-cd-how-to-open) or download. Normal image viewers such as Photos, Preview, and Paint can't open them. OpenMyScan opens a folder of .dcm files in your browser, for free, without uploading anything. Gabriel Theis Founder, OpenMyScan 3 min read Updated October 26, 2026 Beginner ## How do I open .dcm files? A .dcm file may contain one DICOM image, multiple frames, or another DICOM object. To open one, drag the file or its containing folder into openmyscan.com in any browser (Chrome, Safari, Edge, or Firefox). Supported images render locally on your machine, with no install and nothing uploaded. Open your scan free at openmyscan.com. 1. Keep the complete original folder tree, including `DICOMDIR` and all referenced image subfolders if supplied. Do not move or rename its files. 2. Visit `https://openmyscan.com` in any browser (Chrome, Safari, Edge, or Firefox). 3. Drag the folder onto the drop zone. OpenMyScan assembles the stack locally; nothing uploads by default. ## Step 1 — Treat the folder as the unit, not one icon Double-clicking a lone `.dcm` in macOS Preview or Windows Photos fails because those apps expect vacation photos. Medical viewers read the whole directory so slice order, spacing, and orientation stay correct. ## Step 2 — Copy before you open from slow media If the files live on a CD or network drive, copy the folder to your Desktop first. Browsers read thousands of small files faster from an internal SSD, and some corporate laptops block optical drives entirely. ## Step 3 — Scroll and sanity-check After the progress bar finishes, use the slice slider or left/right arrow keys to move through slices. In single view, the mouse wheel zooms. If a series list appears, click each entry. Some studies bundle multiple directions (axial, sagittal, coronal). Our free [DICOM viewer](https://openmyscan.com/en/dicom-viewer) handles each of those orientations natively. Brightness still needs a radiologist's eye; OpenMyScan is not diagnosing you. ## Why won't a .dcm file open on Mac or Windows? **Someone emailed a single tiny `.dcm`** Ask for the complete original study; one file may contain only part of it. **Files have no `.dcm` suffix** That is normal; OpenMyScan reads the file header to detect DICOM instead of relying on filenames. **Drag-and-drop does nothing** Use the folder picker button or try another browser; some locked-down PCs block drag. **I see DICOMDIR but the screen stays blank** Copy the complete original directory tree, keeping `DICOMDIR` and all referenced subfolders in their supplied locations. Select the parent folder; do not move image files beside the index. // open your scan Ready Open your scan right now OpenMyScan runs in your browser. Your files stay on your computer while you review them. [Open viewer](https://openmyscan.com/en/dicom-viewer) ## Common questions ### Is .dcm the same as DICOM? Yes. DICOM is the standard, .dcm is the most common file extension for it. .dic, .dicom, and no-extension files also occur. ### What software do radiologists use? Horos, OsiriX, RadiAnt, Weasis are clinical tools with mass/measurement features. OpenMyScan is the patient-friendly version: same files, simpler UI. ### Can I convert .dcm to JPEG? Yes. OpenMyScan exports any slice as PNG or JPEG, no account or upgrade needed. Open the file, pick the slice, choose Export. ### Can I view my scan on my phone? No. The viewer needs a browser window at least 1200 pixels wide to show images alongside the series list. Use a laptop or desktop, or a tablet only if its browser window meets that width. Rotating an iPad to landscape does not guarantee enough space. Guides remain available on smaller screens. → try it now ## Open *your* scan Your original scan files are read on your device without a scan upload. Local previews and settings can persist after closing the tab; clear this site’s browser data to remove them completely. [Open viewer](https://openmyscan.com/en/dicom-viewer) [Browse all guides](https://openmyscan.com/en/guides) ## Keep reading [All 14 guides →](https://openmyscan.com/en/guides) [G–12 · Understanding What is a DICOM file? DICOM is the file format every MRI and CT scanner produces. It is not a photo. A DICOM image file may hold one image or multiple frames with metadata. Here's the short version. Read guide](https://openmyscan.com/en/guides/what-is-dicom-format) [G–05 · Opening Best DICOM viewer for your scans: free and paid options Compare free and paid DICOM viewers for MRI and CT: OpenMyScan, MicroDicom, OsiriX MD and RadiAnt. Check accounts, local viewing, exports and license terms. Read guide](https://openmyscan.com/en/guides/best-free-dicom-viewer) [G–11 · Sharing How to convert DICOM (.dcm) to JPEG You want to paste a slice into a message, a Google Doc, or email. That means JPEG or PNG, not DICOM. Here's how to export one slice or a whole series. Read guide](https://openmyscan.com/en/guides/how-to-convert-dicom-to-jpeg) OpenMyScan is a viewer for images you already own. It is not a diagnostic tool, is not FDA- or CE-cleared, and does not replace professional medical advice. Always consult your doctor.