This document analyzes and compares different bit carry look ahead adders implemented using Verilog code. It summarizes the performance of 4-bit, 8-bit, and 16-bit carry look ahead adders synthesized on Xilinx. The carry look ahead adder architecture is described, which calculates carry bits in parallel to reduce delay compared to ripple carry adders. Simulation results show that as the bit width increases, the number of slices, LUTs, logic levels, and delay also increase for carry look ahead adders. The carry look ahead adder has the lowest area-delay product, making it suitable for applications requiring low power and high speed.