Tidal Range
Calculate the tidal range, range = high tide height − low tide height, subtracting the lowest from the highest level observed in a tidal cycle. The result, in meters, is the vertical difference between high and low tide — a fundamental parameter for navigation (available draft), port and coastal structure design, tidal energy and intertidal ecology. Spring tides (new/full moon) have maximum range; neap tides (quarter moon), minimum. Some regions have ranges of a few centimeters; others (Bay of Fundy), over 15 meters. Enter the high and low tide heights.
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Tidal range
The tides — the periodic rise and fall of sea level caused by the gravitational pull of the Moon and the Sun on the oceans — are characterised first of all by their range: the vertical difference between high water and low water, simply range = H_high − H_low. That range varies enormously from place to place and over the course of the month. Through the lunar month it swings between spring tides, at new and full moon, when Sun and Moon line up and their pulls add together to produce the largest ranges, and neap tides, at the lunar quarters, when the two pulls partly oppose each other and the range is at its smallest. Geographically, the range depends on the shape of the ocean basins and of the coastline: in the open sea and in enclosed seas (the Mediterranean) it amounts to a few centimetres; in estuaries and funnel-shaped bays that resonate with the tide it is amplified dramatically — the Bay of Fundy, in Canada, has the largest in the world, over 16 metres. Tidal range is vital information for navigation (knowing whether there is enough water under the keel for a ship to cross a bank or enter a port, and when), for the design of ports and coastal structures (which have to work at every state of the tide), for tidal power (which needs large ranges to be viable), for fishing and aquaculture, and for the ecology of the intertidal zone (the strip that is alternately covered and exposed, one of the richest ecosystems on the planet). Tide tables, computed by harmonic analysis of the astronomical constituents, predict these heights accurately. Enter the high-water and low-water heights.
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The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.