Sketch has excellent tools built-in for making sure your content is lined up correctly. It can also be a real blessing to a developer who has received a Sketch document from a designer and needs to get exact pixel measurements done.
When you hold down the Option (⌥) key on the keyboard, Sketch will calculate the distance between the layer you’ve selected and the layer you’re hovering in the Canvas or Layer List. As seen in this screenshot below:
In addition, you can also hold down Command (⌘) along with ⌥ to measure the distance between layers who may not be in the same group or container.
Also, when moving an object Sketch will show you the distance to other objects when it’s equal to other existing distances:
In the same way, if you resize a layer, Sketch will help you by indicating other layers that have the same width or height.