Solid line = floor (spellings that unambiguously belong to the group). Shaded band up to the dashed edge = ceiling (the most it could reach if every ambiguous spelling counted here).
Grant is now well below its former popularity. All-time it's been given to 136,669 U.S. babies, the 480th most common name by sound today, peaking at 3,315 in 1997, with 1,555 in 2025.
Grant has no common alternate spellings by sound.
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).