Boston is about 1.8 times smaller than Osaka.

Osaka is approximately 223 sq km, while Boston is approximately 124 sq km, making Boston 55.61% the size of Osaka.
Tip: This to-scale comparison of Osaka vs. Boston 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.