How to read the band →
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).
Calvin
Calvin is down from its peak but still widely used. All-time it's been given to 229,013 U.S. babies, the 281st most common name by sound today, peaking at 4,940 in 1924, with 2,826 in 2025.
By sound, Calvin also includes the spellings Kalvin.
Rising
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).