The Grantha block spans U+11300–U+1137F, 128 codepoints in Plane 1 (Supplementary Multilingual Plane). 86 are assigned in Unicode 16.0; the other 42 are reserved for future characters.
By script: Grantha (85), Inherited (1).
By general category: 53 other letters (Lo), 17 non-spacing marks (Mn), 16 spacing marks (Mc).
The first 83 arrived in Unicode 7.0 (2014); later additions came in 8.0 (2), 11.0 (1).
Most characters here are combining marks. See combining diacritical marks.
Because it lies outside the BMP, every character here takes four bytes in UTF-8 and a surrogate pair in UTF-16.