Open HDF5 files in your browser
The file science keeps its big arrays in, from satellites and microscopes to simulations and Keras models. Open one right here, with no Python or HDFView. Nothing leaves your device.
Or drop it anywhere on this page
What you'll see
Your HDF5 file opens as its groups and datasets, each with its type and shape, and each dataset opens as a table.
- Every group and dataset • Its type and shape
- The Tree • Attributes and small datasets' values
- Each dataset opens as a table
- Save a dataset as a NumPy array
About HDF5
HDF5 is where instruments, simulations and labs keep large arrays of numbers: NASA's satellite data (.he5), beamline and microscope images, physics and climate models, Keras models' weights and pandas' HDFStore. MATLAB's 7.3 MAT-files, NetCDF-4 and AnnData are HDF5 inside too.
A file is laid out like folders: groups holding datasets, each an array of any number of dimensions in one type, from bytes and floats to strings and records with named fields, with attributes that describe them. Big datasets are kept in chunks, usually packed with gzip, and links point from one group to another, or to another file.
Filepeek reads it in your browser with HDF5's own library. Datasets lists every group and dataset with its type and shape, the Tree shows the attributes and the values of small datasets, and each dataset opens as a table and saves as a NumPy array. Chunks packed with plugins HDF5 doesn't carry, like Blosc or Zstandard, can't be unpacked, and the card names the plugin.
Hierarchical Data Format 5
.h5 • .hdf5 • .he5
Format
- MIME type
- application/x-hdf5
- Made by
- The HDF Group
- Released
- 1998
Inside the file
- Holds
- Groups of datasets, with attributes
- Datasets
- Arrays of numbers, strings and records
- Compression
- gzip, szip and shuffle
- Inside
- MAT-file 7.3, NetCDF-4, AnnData
Opens in every browser
Browsers download HDF5 files, and HDFView needs installing. Filepeek opens them in Chrome, Edge, Firefox and Safari.
- YouChromeOpens through Filepeek
- YouEdgeOpens through Filepeek
- YouFirefoxOpens through Filepeek
- YouSafariOpens through Filepeek
Apps that open HDF5
- WindowsHDFView, free • Python with h5py
- MacHDFView, free • Python with h5py
- iPhone and iPadNo app opens it
- AndroidNo app opens it
Questions
How do I open an .h5 file without Python?
Drop it on this page or choose Peek an HDF5. Every group and dataset shows with its type and shape, with nothing to install.
Can I convert HDF5 to CSV or Excel?
Yes. Open a dataset from Arrays, then choose Export and Save as CSV, Excel, JSON or Parquet. It also saves as a NumPy .npy file.
Why does h5py say 'file signature not found'?
The file doesn't start like HDF5. Files named .hdf are often HDF4, an older format with a similar name that HDF5's tools don't open, and neither does Filepeek. A download that saved a web page instead of the file gives the same error.
What does 'truncated file' mean?
The file is shorter than its header says, as when a copy or a download stops early. HDF5 needs the whole file, so get it again.
Can I see the weights in a Keras .h5 model?
Yes. A Keras model saved as .h5 keeps each layer's weights as datasets, each with its shape, and the model's settings in the file's attributes.
Why won't one dataset open?
Its chunks are packed with a plugin HDF5 doesn't carry, like LZF, Blosc, Zstandard or Bitshuffle, and its row says which. In Python, h5py reads them once hdf5plugin is installed.