TL;DR I'd say it really depends on the context.
What I remember in high-school/secondary school:
We were given problems like
Given length and area of a rectangle, find its width.
(Not exactly rectangle. that's of course more primary/grade school. Can be rectangular prism or whatever.)
The 'formula' is $A =wl$.
The 'equation' is what you get when you plug in the given values for $A$ and $l$. So if you have $A=10$ and $l=7$, then the equation is $10=7w$.
At the time, I thought it was very nit-picky/subjective/conventional/contextual. Now, I still do but I have the 10,000+ rep and bachelor's and master's degrees to complain about it.
According to my secondary school teachers, what you provided is a formula, but that's in the context of filling in the blanks of equation and formula in school.
Conclusion: I'd say it really depends on the context. If you define equation as a statement with an equal sign, then every formula with an equal sign is an equation... By the way, it seems on Wikipedia that there are no inequalities that are formulas.