British Indian Ocean Territory is about 65 times smaller than South Georgia and South Sandwich Islands.

South Georgia and South Sandwich Islands is approximately 3,903 sq km, while British Indian Ocean Territory is approximately 60 sq km, making British Indian Ocean Territory 1.54% the size of South Georgia and South Sandwich Islands.
Tip: This to-scale comparison of South Georgia and South Sandwich Islands vs. British Indian Ocean Territory uses the Mercator projection, which distorts the size of regions near the poles.
Compare further: British Indian Ocean Territory vs. South Georgia and South Sandwich Islands