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Numeric data to HDF5

Create a single selected HDF5 dataset from a numeric matrix or an exported JSON envelope.

Local conversion
Convert filesBuild a pipeline↳ Runs locally

Drop your files here

Make something new. Keep everything private.

Multiple files welcome · processed one at a time

Select a tool to see its supported formats and conversion limits. Large files may exceed your browser’s memory.

Before processing large files

On phones and tablets, start with files under 20 MiB and keep this tab in the foreground. Video, OCR and 3D operations can use several times the input size in memory. Desktop browsers generally have more room, but the 128 MiB job limit is not a guarantee that every file will fit. Smaller batches reduce memory pressure.

✓ No file uploads✓ No signup required✓ On-demand engines

Supported input formats

  • JavaScript Object Notation (.json)
  • Comma-separated values (.csv)

Output format

Hierarchical Data Format 5 (.h5)

Support applies to this conversion direction. Check the limits below for features that may change or be discarded.

Compare all supported formats and conversion limits →

How to use Numeric data to HDF5

  1. Add your supported file using the chooser or drop zone.
  2. Review the settings and conversion limits before processing.
  3. Select Convert files, then download the result.

What to expect

  • 2 million finite numeric elements. CSV requires a rectangular matrix without a header and writes float64.
  • JSON must contain flat data, shape and dtype. Creates a new file with one dataset; does not preserve source attributes.

Engine: h5wasm. The engine may need a first-use download. Your file stays in this browser session.Check conversion engines and offline requirements.

Conversion settings

These settings are available in the converter above.

Dataset path
Inspect the HDF5 file and enter an explicit path, such as /measurements. JSON keeps all dimensions; CSV accepts 1D / 2D only.

About this conversion

Is numeric data to hdf5 free?

Yes. This tool runs on your device without an account or a conversion fee.

Are files uploaded during conversion?

File processing happens locally in your browser. Engines may download their code on first use; your input files are not sent to a conversion server. Read how file privacy works.

What if conversion fails?

Check that the file matches a supported input, review the engine’s limitations and try a smaller representative file. If the engine cannot load, check its engine assets and browser requirements. The app reports failures without switching to a remote converter.

Continue with your output

These tools accept this tool’s output format. Each step has its own settings and fidelity limits.

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