Demonstrated in this paper is a technique for automatic circuit resizing between different technologies. It relies on design knowledge extraction, which renders it very fast compared to full optimization approaches and allows handling of much larger circuits. This technique studies the original design and extracts its major features (basic devices & blocks features, device matching, parasitics, symmetry) and then reproduces a new sized design in the target technology with the same performance as the original design. The migration of a Folded-Cascode amplifier, Low Voltage Delta Sigma A/D and a USB Transmitter is presented in this paper to validate the migration engine.