Should all grid contents be divisible by 8 or an even number?

1. Why use an 8 pixel grid?
2. What is the 8 pixel rule?
3. Does iOS use 8pt grid?
4. How to create stronger layouts with the 8pt grid system?

Why use an 8 pixel grid?

The value of 8 point grid system

It provides a visual hierarchy to elements and drives consistent scalability with fewer decisions to make while maintaining a quality rhythm.

What is the 8 pixel rule?

Pivotal UI uses an 8-point grid system for sizing, spacing, and laying out components relative to one another. This means that any padding, margin, button height, etc. is always a multiple of 8 pixels. This makes it easy to compose Pivotal UI components together neatly and consistently.

Does iOS use 8pt grid?

iOS: Hard & Soft 8-point grids. Achieving vertical rhythm in your UI | by B.

How to create stronger layouts with the 8pt grid system?

When it comes to Type, using the 4pt Baseline Grid alongside the 8pt Grid gives you a much more harmonious vertical rhythm throughout your designs. Simply align your type to a Baseline Grid of 4, which uses a line-height value that is a multiple of 4 (4, 8, 12, 16, 20 etc…)