Multiple lines are treated as fragments of one message (combined in order).
Decode AIS NMEA sentences (Types 1β3 position reports and Type 5 voyage data) at the bit level.
Multiple lines are treated as fragments of one message (combined in order).
Your vote is saved on this device only.
Paste a raw AIS NMEA sentence and this tool unpacks it down to the individual bits, decoding the 6-bit ASCII payload into readable fields. It handles Type 1, 2, and 3 position reports (MMSI, latitude and longitude, speed over ground, course, heading, navigation status) and Type 5 static and voyage data (vessel name, call sign, ship type, draught, and destination).
It is built for marine traffic analysts, AIS receiver hobbyists, integration developers, and students learning the ITU-R M.1371 message format. The decoder is free and runs entirely in your browser, so the sentences you paste are never uploaded to any server and stay on your machine.
No. Decoding happens entirely in your browser, so the sentences never leave your device and nothing is uploaded to a server.
It decodes Type 1, 2, and 3 position reports and Type 5 static and voyage-related messages. Other message types are not covered.
Paste a raw AIS NMEA sentence, such as an !AIVDM or !AIVDO line containing the 6-bit ASCII payload.
AIS messages pack fields into fixed bit ranges per the ITU-R M.1371 standard. Showing the bit-level breakdown lets you verify exactly how each field maps to the payload.
No. The decoder is completely free with no account, sign-up, or usage limits.