DICOM file inspector
Free DICOM file inspector. See the SOP class, transfer syntax, modality, dimensions, compression and study structure of any .dcm file.
What it does
Before you can do anything useful with a DICOM file it helps to know what it actually is. The inspector answers that: what kind of object it holds, how the pixels are encoded, how many studies and series you are dealing with, and whether anything is missing or inconsistent.
It is the tool to reach for when a file will not open somewhere else, when a study seems incomplete, or when you simply want to know what a folder of files contains before you send it on.
Object and encoding
SOP class, transfer syntax, compression type and byte order.
Image characteristics
Dimensions, frames, bits stored and photometric interpretation.
Study structure
How many studies, series and instances, and how they group together.
Problems and personal data
Errors, warnings, missing fields and whether identifying data is present.
How to use it
Load the files
One file, a folder or a ZIP.
Read the summary
Counts, modality, dimensions and whether pixel data is present.
Open the technical detail
SOP class, transfer syntax, bit depth and photometric interpretation.
Go where you need
View the images, browse the tags or anonymise the study.
When people use it
A file will not open in another program
The inspector usually tells you why in one line — most often an unsupported compression.
Checking a study is complete before sending it
Instance counts and gap detection catch missing slices.
Working out what a mystery folder contains
Modalities, series and counts, without opening every file by hand.
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
- 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
What is a SOP class?
It is the code that says what kind of DICOM object a file holds — a CT image, an MR image, a structured report, an encapsulated PDF and so on. The inspector translates the code into its name.
What is a transfer syntax?
It describes how the data is encoded: whether value representations are explicit, which byte order is used, and whether the pixels are compressed and how.
Why does it say the compression is unsupported?
Some DICOM files use JPEG 2000, JPEG Lossless or JPEG-LS. Decoding those in a browser needs large codecs that we deliberately do not ship. The metadata still reads fine; only the image cannot be drawn.
Can it tell me if images are missing from a series?
It flags gaps when the instance numbers in a series are not consecutive, which is the usual sign of a partial download.