Free online IGC to CSV converter

What the IGC format is

IGC is the standard flight-recorder format used mainly for paragliding, hang gliding, sailplane, and other aviation activities. Flight instruments and tracking programs such as XCSoar, SeeYou, LK8000, FlySkyHy, and various logger devices can create IGC files.

An IGC file is plain text but has a specialized record structure. B records contain time, latitude, longitude, pressure altitude, and GPS altitude; A, H, I, J, and G records contain device information, headers, extensions, and security data. The file usually has an .igc extension and is encountered when downloading a flight from a GPS logger or retrieving a track from flight-analysis software.

What the CSV format is

CSV stores tabular data as rows and comma-separated columns. A converted flight log can contain fields such as UTC time, latitude, longitude, pressure altitude, GPS altitude, and selected IGC metadata.

CSV opens in Microsoft Excel, LibreOffice Calc, Google Sheets, GIS software, databases, and Python or R. It is useful for filtering a flight, calculating statistics, plotting an altitude profile, importing coordinates, or combining several logs. CSV does not preserve the IGC security signature or every specialized record unless the converter explicitly exports those fields.

How to actually convert IGC to CSV

Use the built-in online converter

1. Open the IGC-to-CSV converter on 101convert.com.
2. Select or drag the .igc file into the upload area.
3. Choose CSV as the output format and start the conversion.
4. Download the resulting .csv file and open it in a spreadsheet or analysis program.

This option requires no installed software. Check the exported column names before importing the file into a database or GIS application.

Convert with a local Python script

For repeatable processing or sensitive flight data, parse the B records locally. The following script writes UTC time, coordinates, pressure altitude, and GPS altitude:

import csv
from datetime import time

input_name = "flight.igc"
output_name = "flight.csv"

def latitude(value, hemisphere):
    degrees = int(value[:2])
    minutes = float(value[2:]) / 1000
    result = degrees + minutes / 60
    return -result if hemisphere == "S" else result

def longitude(value, hemisphere):
    degrees = int(value[:3])
    minutes = float(value[3:]) / 1000
    result = degrees + minutes / 60
    return -result if hemisphere == "W" else result

with open(input_name, encoding="ascii", errors="replace") as source, open(output_name, "w", newline="", encoding="utf-8") as target:
    writer = csv.writer(target)
    writer.writerow(["utc_time", "latitude", "longitude", "pressure_altitude_m", "gps_altitude_m"])
    for line in source:
        if not line.startswith("B") or len(line.rstrip()) < 35:
            continue
        record = line.rstrip()
        hhmmss = record[1:7]
        writer.writerow([
            f"{hhmmss[:2]}:{hhmmss[2:4]}:{hhmmss[4:6]}",
            latitude(record[7:14], record[14]),
            longitude(record[15:23], record[23]),
            int(record[25:30]),
            int(record[30:35])
        ])

Save it as igc_to_csv.py, place it beside the IGC file, change the two filenames if necessary, and run python igc_to_csv.py. The script assumes the standard IGC B-record layout and altitude values in metres.

Quality and compatibility considerations

• IGC coordinates use degrees and thousandths of a minute, not decimal degrees. A correct converter must apply the N/S and E/W hemisphere signs.
• Times in B records are normally UTC and have one-second resolution. Some loggers record fixes more frequently through extension records, so a basic converter may omit sub-second or extra sensor data.
• Pressure altitude and GPS altitude are different measurements. Keep both columns instead of treating them as interchangeable.
• CSV has no universal column or date standard. Confirm the delimiter, decimal separator, character encoding, coordinate order, and header names required by the receiving program.
• Conversion changes the data representation and can remove IGC headers, task records, events, extensions, and the original security signature. Keep the original .igc file for certified flight records or later reprocessing.