Are there any significant differences between the Audi A4 and A3 models?

I've been comparing the Audi A4 and A3 models and noticed they have similar features and specifications. However, I want to know if there are any substantial differences that can affect my decision in purchasing either one.

Both Audi A4 and A3 models have a sleek and stylish exterior design, as well as a luxurious interior. However, the A4 has a larger body size and offers more spacious seating for passengers. So, if you value comfort and space, the A4 might be a better option for you.