ðə hˈaɪt ʌv ɛɡzˈɪstɪŋ lˈaɪthaʊsᵻz ɪz ɛkspɹˈɛst ɪn tˈuː mˈɛʒɚz: ðə hˈaɪt ʌvðə tˈaʊɚɹ ɪtsˈɛlf, ænd ðə dˈɪstəns fɹʌmðə fˈoʊkəl plˈeɪn ðæt ˈɪz, ðə sˈɛntɚ ʌvðə lˈaɪt sˈoːɹs tə ðə wˈɔːɾɚ.
The height of existing lighthouses is expressed in two measures: the height of the tower itself, and the distance from the focal plane (that is, the center) of the light source to the water.