free · in-browser · no upload

DICOM to JSON
Converter

Drop your DICOM file. We'll convert it to JSON right here in your browser, your file never leaves your device.

or drop your file

Select your file here to get started

or drop your file here.

Accepts .dcm, .dicom

nothing uploaded no file size cap no signup

How it works

Three steps. No upload, no signup.

1
Drop your file
Click the dropzone above or drag a DICOM from your desktop. Files of any size, there's no upload, so there's no upload limit.
2
Convert in your browser
The conversion runs entirely in this tab using JavaScript and WebAssembly. Your file never touches our servers, we don't have any.
3
Download
Get your JSON the moment the conversion finishes. Convert another, or close the tab.

Files stay on your device

Your file is never uploaded. The entire conversion runs in your browser using WebAssembly. We can't see what you convert because we have no server to see it.

No file size limit

Server converters cap free users at 1-2 GB and gate larger files behind a paid plan. Since nothing uploads, our limit is whatever your browser can handle.

Free, no signup, no ads on conversions

No account required. No watermark on the output. No queue. Drop a file, get a converted file.

Why convert DICOM → JSON

What this conversion is actually for

Sometimes you don't want the pixels — you want the metadata: patient ID, study date, modality, scanner model, acquisition parameters, window/level presets, study/series/instance UIDs. Researchers building DICOM manifests, hospital IT auditing PACS exports, programmers triaging anomalies in a tag dump — all need the DICOM header as structured data. Convert here, get JSON your code can parse.

A real example

You're building a tool that indexes a hospital research archive of 50,000 DICOMs. For each file, you need to extract Modality, StudyDate, and StudyDescription to build a searchable database. Loop over the files, run each through this converter, parse the JSON output, insert into your DB. Patient identifiers never leave the radiologist's workstation.

Troubleshooting

I expected to see private vendor tags (Siemens, GE, Philips) in the output.

We currently extract only the standard DICOM Data Dictionary tags. Private group tags (group numbers ≥ 0x0009 with odd group number patterns) are skipped. If you need vendor-private fields, use pydicom or dcmtk's `dcmdump` for a full hex-level tag dump.

PatientName contains caret characters like "DOE^JOHN".

We strip the carets in the JSON output ("DOE JOHN"). DICOM's Person Name (PN) VR uses `^` to separate family name / given name / middle name / prefix / suffix. If you need the original caret-separated form for downstream parsing, the raw bytes are recoverable from the DICOM file directly via dcmtk's `dcmdump`.

Formats involved

About DICOM and JSON

DICOM, Digital Imaging and Communications in Medicine

DICOM is the universal medical imaging format — every X-ray, CT scan, MRI, ultrasound, mammogram, PET scan, and most pathology slides from every modern PACS (Picture Archiving and Communication System) is DICOM. The format wraps a pixel-data payload (the actual image) with a rich metadata header carrying patient identifiers, study/series/instance UIDs, imaging modality, acquisition parameters, window/level presets, and per-vendor private tags. Spec maintained by NEMA (National Electrical Manufacturers Association); first published in 1985 as ACR-NEMA 1.0, became DICOM 3.0 in 1993, still actively versioned today. Wire format: 128-byte preamble + `DICM` magic + tagged-value stream where each tag is a (group, element) pair indexing into the DICOM Data Dictionary.

How to open

Hospital workstations open DICOM natively. For desktop viewing: RadiAnt, OsiriX (macOS), Horos (macOS, free), MicroDicom (Windows, free), Weasis (cross-platform Java). For programmatic access: dcmtk (CLI), pydicom (Python), dcm4che (Java). The free MyChart-equivalent apps from most hospital systems also surface DICOMs from your own scans.

Full DICOM format guide →

JSON, JavaScript Object Notation

JSON is a lightweight text format for structured data, nested objects, arrays, strings, numbers, booleans. It's the lingua franca of web APIs, configuration files, and data interchange between programs. Human-readable when formatted, machine-parseable in every programming language, and roughly half the size of equivalent XML.

How to open

Any text editor reads JSON. Browsers display .json files in a formatted tree view. VS Code and similar editors highlight syntax.

Full JSON format guide →

Related tools

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FAQ

Common questions

Is this DICOM → JSON converter really free?

Yes. No signup, no watermark, no daily file count limit. Every conversion runs in your browser, your file never touches our servers because there are no servers.

Where does my file go when I convert it?

Nowhere. The conversion runs entirely in your browser using JavaScript and WebAssembly. Your file is never uploaded to our servers. We don't have any servers handling files, there's nothing for us to log, store, or accidentally leak.

What's the maximum file size?

Whatever your browser can hold in memory. Practically, this means a few hundred MB on most computers, significantly larger than the 1-2 GB caps that server-upload converters charge for. Very large files (multi-GB) may require closing other browser tabs first.

Why convert DICOM to JSON?

Medical imaging interchange — sharing scans between hospitals, second opinions, research datasets, patient downloads from EHR portals. API responses, configuration files, structured data interchange. The most common reason to convert is compatibility, JSON works in places where DICOM doesn't, or vice versa.

How do I open a DICOM file in the first place?

Does this work offline?

Once the page is loaded, the conversion itself runs entirely offline. The first time you use a tool, your browser downloads the conversion library (a one-time cache). If you reload while offline, the page won't load, but you can install the site as a Progressive Web App for full offline use.

Can I convert multiple files at once?

Single file at a time for now. Batch conversion is on the roadmap, for now, drop one file, download the result, then convert the next.

DICOM to JSONConverter