Isle of Man is about 1,656 times smaller than Tanzania.

Tanzania is approximately 947,300 sq km, while Isle of Man is approximately 572 sq km, making Isle of Man 0.06% the size of Tanzania. Meanwhile, the population of Tanzania is ~63.9 million people (63.8 million fewer people live in Isle of Man).
Tip: This to-scale comparison of Tanzania vs. Isle of Man uses the Mercator projection, which distorts the size of regions near the poles.