Compare between Apple Mac computers
Apple's official website has a compare section for Macs where you can compare between three different models of Mac simultaneously. You can access it by going to the following link:


https://www.apple.com/mac/compare/


When making a purchase decision, the first distinction that you have to make is whether you are looking to buy a desktop or a laptop.

Broadly speaking, Apple currently makes three kind of laptops:


MacBook Air - A 13" ultra-portable.
13" MacBook Pro - A lightweight laptop for professionals.
16" MacBook Pro - A spec heavy laptop geared towards users needing extreme performance.


and three kinds of desktops:


Mac mini - A bare bones lunch-box size computer sans display, keyboard and mouse.
iMac - A fully integrated desktop computer.
Mac Pro - An expandable desktop tower for users requiring extreme performance.


Once you have filtered down to the determine computers that you are looking to choose from, head over to the Mac - Compare Models web-page and select the desired ones. You can compare upto three different computers at a time.

Here's a comparison between a 16" MacBook Pro, a 13" MacBook Pro and a 21.5" iMac looks like: