Seattle Population 2024 Projection Matrix. Ever wonder how many people live in seattle, wa and how fast that number changes? From july 1, 2021, to july 1, 2022, seattle had a net gain of about 17,750 people, bringing the total population to 749,000.

That’s growth of more than 225,000 residents in 20 years. Seattle’s population increased by 16,700, representing more than.