Is there something wrong with my script or is Bash much slower than Python?

I was testing the speed of Bash and Python by running a loop 1 billion times. $ cat python.py #!/bin/python # python v3.5 i=0; while i<=1000000000: i=i+1; Bash code: $ cat bash2.sh #!/bin/bash # bash v4.3 i=0 while [[ $i -le 1000000000 ]] do let i++ done Using the time command I found out that the Python code takes just 48 seconds to finish while the Bash code took over 1 hour before I killed the script. Why is this so? I expected that Bash would be faster. Is there something wrong with my script or is Bash really much slower with this script?