Plato coincidences

So, this may be a stupid question but here it goes...

I just read the gravity of my latest batch... 1.026 (6.5 plato) from the reading two days ago 1.057 (14.25 plato) and beertools says that I am about at 4.0% abv....

so heres my question.... the change in degrees plato is about 8... the abv is half that of the change in degrees plato... does this always work out to be a quick guestimate for abv without having to pull out a computer????

Thank you for your time

The standard equation tossed around to approximate ABV is (og - fg * 131.25 ). The relationship between gravity and plato is not quite linear, though 4 points sg is roughly equivalent to a degree of plato.

Very roughly, a point of plato drop is about 0.525% alcohol.

soooooo, what you're saying is..... kind of.... ball park works for me, well atleast until I get to the computer