Making a UIButton a % of the screen size

Question

I noticed certain button sizes look great on one the iPhone 5 simulator but do not look as good on the iPhone 6 simulator and this is because the heights or constraints that

Answer 1

1. Ctrl drag from button to superview and select Equal Widths

2. Open Size Inspector edit Equal Widths constraint and set multiplier to 0.4. And you will see something like this:

3. Add missing constraints and update frames.