South Africa is about 3.9 times bigger than New Mexico.

New Mexico is approximately 314,310 sq km, while South Africa is approximately 1,219,090 sq km, making South Africa 288% larger than New Mexico. Meanwhile, the population of New Mexico is ~2.1 million people (55.5 million more people live in South Africa).
Tip: This to-scale comparison of New Mexico vs. South Africa uses the Mercator projection, which distorts the size of regions near the poles.