Kansas is about 1.6 times smaller than Vietnam.

Vietnam is approximately 331,210 sq km, while Kansas is approximately 211,900 sq km, making Kansas 63.98% the size of Vietnam. Meanwhile, the population of Vietnam is ~101.6 million people (98.6 million fewer people live in Kansas).
Tip: This to-scale comparison of Vietnam vs. Kansas 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.