Do dreads make your hair look shorter? Yes, it can, but not necessarily. The dreadlocks themselves won't make your hair look shorter, but if your hair has a tighter curl or a different texture, then it can look a little shorter than what it would normally be if it wasn't dreaded, but it always depends on your texture. Some textures are a little softer.
They may look about the same length as they did when your hair was straight. Textures that are a little curlier may look a little shorter, but that doesn't necessarily mean that the dread itself is shorter or that the dreadlocks themselves are making your hair look shorter. It really just depends on your texture. So although dreadlocks may make your hair look shorter, it doesn't actually change the actual length of your hair.