Is a ratio a rate

is a ratio sometimes, always, or never a rate? also, is a rate sometimes, always, or never a ratio?

It depends on how the words are used. "The crime rate is increasing" is not a ratio but the "the crime rate doubled" says the ratio between now and an earlier date is 2:1.

Ratio is more of a mathematical distribution of values where rate is most often about frequency. You can also use "rate" as a verb. "Rate the computers by their features," wouldn't produce a ratio.

Rate can also mean an angry outburst.

I would say, "sometimes."