DICOM validator
Free DICOM validator. Check whether a .dcm file is valid, damaged, incomplete or uses an unsupported compression. Plain summary plus technical detail.
What it does
When a file will not open, the useful question is whether the file is broken or whether the software simply cannot read it. Those are very different problems and the fix is different in each case.
The validator answers that directly. You get one of three verdicts — valid, valid with warnings, or invalid — plus the specific reasons behind it, written so you can act on them without knowing the standard by heart.
A clear verdict
Valid, valid with warnings, or invalid and unsupported.
Specific reasons
Missing identifiers, zero dimensions, inconsistent bit depths, truncated pixel data and more.
Study-level checks
Duplicated instances, gaps in a series and studies that mix modalities.
Summary first, detail on demand
A plain summary you can act on, with the technical view one click away.
How to use it
Load the file or study
One file, several, or a ZIP.
Read the verdict
The headline answer, colour-coded.
Work through the findings
Each one explains what is wrong and how serious it is.
Act on it
Open a valid file in the viewer, or go back to whoever supplied a broken one.
When people use it
A download that may have been cut short
Truncated pixel data and missing instances are both detected.
Deciding whether to ask for the study again
Knowing the file is genuinely damaged saves a lot of guessing.
Checking files before importing them somewhere
Catch the problems before the import fails.
Supported files
- Uncompressed DICOM (implicit and explicit VR, little and big endian)
- RLE lossless compression
- JPEG baseline and extended, decoded by your browser
- Files with a .dcm extension, and DICOM files with no extension at all
- ZIP archives containing a whole study or several series
Limitations
- This is a practical check, not a full conformance test against the DICOM standard. It looks for the problems that actually stop files from being used.
- JPEG Lossless, JPEG-LS, JPEG 2000 and deflated transfer syntaxes are not decoded — they need heavy codecs we deliberately do not ship. You will get a clear message instead of a blank screen.
- This is a technical tool. It does not read your scan, does not look for findings and does not produce any diagnosis.
- Very large studies of several hundred megabytes may be slow, because all the work happens on your own machine.
Privacy and security
Processed in your browser — nothing is uploaded
Your files never leave your device. Everything runs inside your browser using JavaScript — there is no upload, no server copy and no queue.
Because nothing is uploaded, there is nothing for us to store or delete. Closing the tab removes the files from memory.
We never put file names, patient identifiers or metadata values into analytics or logs. Product events only count how many files were opened.
If you later choose the paid AI explanation, that is a separate, explicit step: you decide which files to attach and nothing is sent until you confirm.
Frequently asked questions
How do I know if my DICOM file is valid?
Load it here. You get a verdict plus the specific findings behind it, without installing anything.
My file is "valid with warnings" — is that a problem?
Usually not. Warnings cover things like missing optional fields, personal data being present or a compression we cannot decode. The file itself is structurally fine.
What makes a file invalid?
Missing required identifiers, zero image dimensions, inconsistent bit depths or less pixel data than the file declares — typically the result of a truncated download.
Does it check the whole standard?
No. It checks the things that break real workflows. A full conformance test needs dedicated clinical tooling.