Saint Vincent and the Grenadines is about 5 times bigger than Guernsey.

Guernsey is approximately 78 sq km, while Saint Vincent and the Grenadines is approximately 389 sq km, making Saint Vincent and the Grenadines 399% larger than Guernsey. Meanwhile, the population of Guernsey is ~67,491 people (33,478 more people live in Saint Vincent and the Grenadines).
Tip: This to-scale comparison of Guernsey vs. Saint Vincent and the Grenadines uses the Mercator projection, which distorts the size of regions near the poles.