Tuvalu is about 7 times smaller than District of Columbia.

District of Columbia is approximately 177 sq km, while Tuvalu is approximately 26 sq km, making Tuvalu 14.69% the size of District of Columbia. Meanwhile, the population of District of Columbia is ~601,723 people (590,179 fewer people live in Tuvalu).
Tip: This to-scale comparison of District of Columbia vs. Tuvalu uses the Mercator projection, which distorts the size of regions near the poles.