Admiralty Tide Tables

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The Admiralty Tide Tables , ATT for short , are the tide tables of the United Kingdom Hydrographic Office (UKHO). They offer almost worldwide coverage. With the help of the ATT it is possible to calculate the tides in advance for the entire globe using a uniform method . The ATT are internationally regarded as the standard work on tidal calculations .


The complete work is divided into eight volumes:

Method of calculating tides

The process of calculating the tide is as follows:

Part 1 of the Admiralty Tide Tables contains tide information for certain reference locations, the so-called standard ports . The information includes:

  • Name of the reference location
  • Information about how big the spring tide delay is
  • a tide curve for spring and nip tides
  • Coordinates of the reference location
  • Time zone
  • Month, day and day of the week
  • Information on the moon phase (only main phases, i.e. new moon, full moon and the two half moons)
  • Time of the first flood
  • Time of the first low tide
  • Time of the second flood
  • Time of the second low tide
  • Height of the tide.

The tides for the reference locations can thus be read off easily without prior knowledge. However, the reference locations only include a few large locations.

Locations of the Admiralty Tide Tables that are not reference locations are referred to as secondary ports . For the connection locations, the time and height differences to the reference locations are given in Part 2 of the Admiralty Tide Tables. The values ​​for the connection locations must therefore be calculated individually in relation to the reference locations.


The time and time zone calculation of the ATT differs somewhat from the usual calculation; the time zones have different names. Here are some examples:

The ATT basically do not take into account the summer time of a country, the navigator has to convert any existing summer time into standard time in order to be able to use the time from the ATT.

Web links

Individual evidence

  1. Lutz Böhme: Tide calculations with the Admiralty Tide Tables (PDF; 517 kB)