The size of hoop earrings considered classy depends on personal style and occasion. Smaller hoop earrings, typically up to 1 inch in diameter, offer a classic and understated look. Medium-sized hoops, around 1-2 inches, provide a balance between elegance and boldness, suitable for many settings. Larger hoop earrings, above 2 inches, can make a statement and are often chosen for more formal or fashionable occasions. Ultimately, what's considered classy varies from person to person.