I would say that a college would be a safety if your SATs CR plus Math are in the top 25% for that school. This is based on probabilities, nothing is certain. If your SATs are in the middle 50% between the 25th and 75th percentiles, then the school is a match (in terms of selectivity). If your SATs are below the 25th percentile but within 50 points of the 25th percentile, then the school is a reasonable reach. If your SATs are more than 50 points below the 25th percentile, then the school is a long shot and admission would probably require some kind of hook or other strong qualification.
Of course, there are other factors that relate to “fit”:
Does the school offer your preferred major?
Is it an acceptable distance from home?
Is it in the type of environment (urban, suburban, rural)?
Is it in a desirable part of the country? (seasons, near ocean or mountains, etc.).
Can you somehow find a way to pay for expenses?
I think it is most important that the school offers your major.
The second most important factor is selectivity. Go to the most selective school that you can. Selectivity is correlated with quality. If the school keeps their SAT and ACT scores secret for some reason, then use graduation rate as a proxy for selectivity.
Third most important is distance from home.
Affordability is mostly subjective. If you and your parents really want the best school for you, they should be able to find a way to pay for it. For private schools, ignore sticker price. Instead, find the net price for your income level after financial aid.
I invite others to give their thoughts on this. My basic premise is that young people should become all they are capable of becoming. I want young people to reach their full potential.