Unlike Journal Impact Factor which calculates scholarly significance of journals, the H-Index measures scholarly impact of an individual author's work. The H-Index measure both the number of publications of an author and the number of citations of the publications. It is equivalent to the number of citations that are equal to or greater than the number of papers. For example, an H-Index of 5 would mean that an author has published five papers each of which has been cited at least five times. You can find your H-Index by searching in Web of Science, Scopus, or Google Scholar. The H-Index may vary in each of these sources because they index different publications. The famous scientist Stephen Hawking has an H-Index of 72 in Scopus, 76 in Web of Science, and 130 in Google Scholar. This is because Google Scholar includes a much broader universe of publications than Scopus or Web of Science.
Interestingly, the misspelling in the title raises the question whether "altmetrics" might better be referred to as "allmetrics" because bibliometrics and altmetrics can be seen as complimentary rather than in opposition. Using both may provide a more complete picture of an author's scholarly influence than either alone could provide.