Saint Vincent and the Grenadines is about 3.8 times bigger than Montserrat.

Montserrat is approximately 102 sq km, while Saint Vincent and the Grenadines is approximately 389 sq km, making Saint Vincent and the Grenadines 281% larger than Montserrat. Meanwhile, the population of Montserrat is ~5,414 people (95,555 more people live in Saint Vincent and the Grenadines).
Tip: This to-scale comparison of Montserrat vs. Saint Vincent and the Grenadines uses the Mercator projection, which distorts the size of regions near the poles.