South Africa is about 1.3 times bigger than Tanzania.

Tanzania is approximately 947,300 sq km, while South Africa is approximately 1,219,090 sq km, making South Africa 29% larger than Tanzania. Meanwhile, the population of Tanzania is ~63.9 million people (6.3 million fewer people live in South Africa).
Tip: This to-scale comparison of Tanzania vs. South Africa uses the Mercator projection, which distorts the size of regions near the poles.
Our free app, MapSize by MyLifeElsewhere — compare any two places, to scale on your mobile device.