Cosmo is a distinctive boys' name in England & Wales, ranking #639 in 2025 with 57 recorded births. The name reached its all-time peak in 2025 with 57 births ranking #639. Since 1996, the popularity has increased by 1,040.0%. In 2025, approximately 1 in every 4,771 boys born was named Cosmo. STABLE Recent data shows the name is currently stable.