Nauru is about 12 times smaller than Niue.

Niue is approximately 260 sq km, while Nauru is approximately 21 sq km, making Nauru 8.08% the size of Niue.
Tip: This to-scale comparison of Niue vs. Nauru 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.