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MegaRows

All tools: view, convert and plot data files

Every MegaRows tool in one place, for CSV, Excel, JSON, MATLAB, Parquet, HDF5 and LabVIEW TDMS files with millions of rows. They are free, need no account, and run in your browser.

Your files never leave your device

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CSV plotter

Open a CSV, Excel, TXT, JSON, MATLAB, Parquet, HDF5 or LabVIEW TDMS file with millions of rows and plot it in several linked charts, with zoom and statistics.

View files

Open big data files in your browser and scroll, search or plot them.

  • Large CSV viewer

    Open a CSV with millions of rows in your browser: scroll every row, see each column’s type and statistics, chart any column.

  • MATLAB .mat file viewer

    Open v4 to v7.3 .mat files without MATLAB and plot any signal.

  • Parquet viewer

    Open large .parquet files, see the schema at once and plot millions of rows, without Python.

  • TDMS viewer

    Open .tdms files from LabVIEW, DIAdem and DAQmx loggers: every group, channel and property, each channel plotted against its time.

  • HDF5 viewer

    Open .h5, .hdf5 and NetCDF-4 .nc files: every group, dataset and attribute, each group’s datasets plotted against their time.

Convert

Turn engineering and analytics files into a CSV that Excel, Python or R can read, or a .mat file for MATLAB.

  • MAT to CSV

    Convert the signals of a .mat file, v4 to v7.3, to a CSV for Excel or Python, without MATLAB.

  • Parquet to CSV

    Convert a .parquet file to CSV in your browser, with the columns you pick.

  • TDMS to CSV

    Convert the channels of a .tdms file to CSV, a group at a time, with its time column, without LabVIEW or Excel add-ins.

  • HDF5 to CSV

    Convert the datasets of an .h5 or NetCDF-4 file to CSV, a table at a time, with its time column, without Python.

  • Excel to CSV

    Convert any sheet of an .xlsx or .xlsm workbook to CSV, with the saved results of formulas, real dates and 15 significant digits.

  • JSON to CSV

    Convert JSON and JSON Lines files to CSV: nested fields become columns named by their path, arrays stay as JSON text.

  • CSV to MAT

    Convert a CSV, Excel, JSON or Parquet file to a MATLAB .mat file: a field per column, with names and units, every row.

CSV tools

Merge, split, count, summarise and chart CSV files, including ones spreadsheets cannot handle.

  • Merge CSV files

    Append many CSV files into one, even with different columns or separators.

  • Split CSV files

    Split a CSV too big for Excel into parts of 1,000,000 rows, parts of a size you choose, or one file per value of a column.

  • CSV row counter

    Count the lines in a CSV, TSV or TXT file of any size.

  • CSV statistics

    Count, missing values, min, max, mean, standard deviation, RMS and peak to peak of each number column, for the whole file or the rows you zoom into.

  • CSV histogram

    A histogram of any number column, with automatic bins or 10 to 200 of them, and each bin’s count as a table.

  • CSV too large for Excel?

    Open every row of a CSV beyond Excel’s 1,048,576-row limit, or work around the limit in six other ways.

  • Sample data files

    Download made-up UK weather as CSV, Excel, MATLAB, TDMS, HDF5 and Parquet files, free to use, and plot each one online.

Analyse

Signal maths on your device, checked against the reference libraries.

  • FFT and PSD from a CSV

    Turn a signal column into an FFT spectrum or a PSD with Grms, with results checked against SciPy.

  • PSD calculator

    Turn a vibration column into a power spectral density (Welch) in g²/Hz, with the Grms of any band and a dB view.

  • Spectrogram from CSV

    See how the frequencies of a measured signal change over time, as a heat map in dB, with the window and range you choose.

  • FRF and coherence

    Pick an input and an output column and get the frequency response (H1, H2, magnitude and phase) and their coherence.

  • How we check our maths

    Every calculation checked against NumPy and SciPy, with the results and the largest differences on one page.

Coming soon

  • CSV to Excel and PDF reports
  • Compare two versions of a CSV

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