If Pluto is a planet, so would be Eris, Sedna, Haumea, Makemake, Chorion, and Pallas.
So how many planets are in our solar system?
8 (or 9 if you include the one that almost certainly exists in the Kepler belt that is about the size of Neptune)
Or 15 (16 once again if you include the highly probable 5th Gas Giant)
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It's currently classified as a dwarf planet, and is not included in the planet count. Another note, it's moon is the same size as it is.