Kolby is a distinctive girls' name in United States, ranking #4192 in 2015 with 35 recorded births. The name reached its all-time peak in 2000 with 55 births ranking #2690. Since 1996, the popularity has decreased by 12.5%. In 2015, approximately 1 in every 50,990 girls born was named Kolby. STABLE Recent data shows the name is currently stable.