If Jesus was crucified on April 3, 33 AD and was 30 years old at that time, you would subtract 30 years from 33 AD to estimate his birth year.
33 AD - 30 years = 3 AD.
So, according to this calculation, Jesus would have been born around 3 AD. However, it's commonly noted that Jesus is traditionally thought to have been born a few years earlier than 1 AD, often cited as around 4 to 6 BC. The exact year of his birth is debated among scholars.