How accurate are device emulators in browsers?

Question

css

In google chrome, Apple iPhone 6 has dimensions of 375x627, but is it really so?
That is, the dimensions are probably accurate, but are they accurate taking into account the browser in which
the application-site is viewed? Or, nevertheless, these tools can only set the
limits of real sizes, and we ourselves must figure out in our mind how it will be in the original?

Answer 1

All emulators, this is from the area - most likely everything will be like this. There were bugs on ios7 with vh and vw units that I could not catch in more than one emulator. But in general, this is a natural guideline.