Stockholm is about 1.7 times bigger than Boston.

Boston is approximately 124 sq km, while Stockholm (map shows its 47 named neighbourhoods; the area covers the whole city) is approximately 207 sq km, making Stockholm 67% larger than Boston.
Tip: This to-scale comparison of Boston vs. Stockholm 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.