# Tidal gate calculator (Rule of twelfths)

This calculator calculates tidal gates using the rule of twelfths, estimating the height of the tide at any time, given only the time and height of high and low water. The rule is a rough approximation only and should be applied with great caution when used for navigational purposes. Officially produced tide tables should be used in preference whenever possible.

### Tidal gate calculator (Rule of twelfths)

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Digits after the decimal point: 1
Tidal gate open time

Tidal gate close time

Tidal gate duration

Rule of twelfths