Kolby is a distinctive girls' name in United States, ranking #4749 in 2009 with 31 recorded births. The name reached its all-time peak in 2000 with 55 births ranking #2690. Since 1996, the popularity has decreased by 22.5%. In 2009, approximately 1 in every 59,254 girls born was named Kolby. STABLE Recent data shows the name is currently stable.