South Georgia and South Sandwich Islands is about 600 times bigger than Gibraltar.

Gibraltar is approximately 7 sq km, while South Georgia and South Sandwich Islands is approximately 3,903 sq km, making South Georgia and South Sandwich Islands 59,946% larger than Gibraltar.
Tip: This to-scale comparison of Gibraltar vs. South Georgia and South Sandwich Islands uses the Mercator projection, which distorts the size of regions near the poles.
Compare further: South Georgia and South Sandwich Islands vs. Gibraltar