Mercer Island, WA demographics:
population, income, and more

Total population
25,307
0.1% year-over-year change
Median household income
$219,069/yr
8.3% year-over-year change
Housing units
10,609
1.5% year-over-year change

Mercer Island population

How many people live in Mercer Island

Mercer Island is home to 25,307 residents, according to the most recent Census data. Gender-wise, 47.6% of Mercer Island locals are male, and 52.4% are female.

Total population
25,307
0.1% year-over-year change
Gender ratio
Male
47.6%
12,056
Female
52.4%
13,251
Value Percent YoY change
Male 12,056 47.6% 2.7%
Female 13,251 52.4% -2.1%
A higher population often means more rental variety and livelier areas. The gender balance—how many men live here compared to women—can reveal a lot about the community and the lifestyles of its residents. Use this info to get a sense of the area's pace and personality.

Age demographics

The median age in Mercer Island is 46, with the population distributed as follows: about 15.8% are children under 15, then 12.2% are in the 15 to 24 age group. Adults between 25 and 44 make up 20.3% of the population, while another 29.5% fall into the 45 to 64 bracket. Finally, around 22.2% are 65 or older.

Median age
46.4
Age breakdown
Under 15
15.8%
15 to 24
12.2%
25 to 44
20.3%
45 to 64
29.5%
Over 65
22.2%
Value Percent YoY change
Under 15 3,997 15.8% -10.2%
15 to 24 3,080 12.2% 16.1%
25 to 44 5,147 20.3% -0.2%
45 to 64 7,473 29.5% -3.0%
Over 65 5,610 22.2% 5.6%
The age composition helps you get insight into who lives in the area. A younger population might mean a more active, fast-paced vibe, while an older one could suggest a quieter, slower lifestyle. If there's a balanced makeup, you’re likely to find a variety of services, housing types, and community spaces that cater to different life stages.

Racial makeup

In Mercer Island, 71.8% of the population are US-born citizens, while 17.6% have gained naturalized citizenship. At the same time, 10.6% of residents are non-citizens. As for race, 63.6% of locals are Caucasian, 0.9% are African American and 24.5% have Asian roots. There’s also a share of 10.1% that includes residents with two or more races.

Citizenship
U.S.-born citizens
71.8%
Non-U.S.-born citizens
17.6%
Non-citizens
10.6%
Value Percent YoY change
U.S.-born citizens 18,177 71.8% -2.2%
Non-U.S.-born citizens 4,448 17.6% 7.2%
Non-citizens 2,682 10.6% 5.3%
Racial breakdown
White
63.6%
Black or African American
0.9%
American Indian and Alaska Native
0%
Asian
24.5%
Native Hawaiian and other Pacific Islander
0%
Two or more races
10.1%
Other
0.9%
Value Percent
White 16,085 63.6%
Black or African American 234 0.9%
American Indian and Alaska Native 6 0%
Asian 6,205 24.5%
Two or more races 2,560 10.1%
Other 217 0.9%

Households in Mercer Island

A peek inside Mercer Island households

Mercer Island has 10,068 households, with an average of 2 members in each. Of these, 69.8% are families, while the remaining 30.2% are made up of individuals living alone or with non-relatives, such as roommates.

Households stats

Total households
10,068
1.8% year-over-year change
Average people per household
2
Non-family households
3,041
Family households
7,027
Value Percent YoY change
Non-family households 3,041 30.2% 6.0%
Family households 7,027 69.8% 0.0%
The mix between family and non-family households gives a glimpse into daily life. A higher percentage of families might mean more parks and schools, while more non-family setups can mean flexible housing and diverse living styles. For renters, this can signal what kinds of homes are common and can help you figure out if the area matches your lifestyle.

Housing in Mercer Island

The housing landscape of Mercer Island

Mercer Island's housing consists of 10,609 units, with 66.7% being detached single-family homes ideal for those wanting space. Attached options, including duplexes and townhouses, make up 0.3% and offer a more compact, shared living style. Then there are the multifamily buildings in the area, and for those seeking flexibility, non-traditional options like mobile homes account for 0.7% of the housing landscape.

Housing units
10,609
1.5% year-over-year change
Housing types
Value Percent
1 unit, detached 7,076 66.7%
1 unit, attached 33 0.3%
2 units 11 0.1%
3 or 4 units 72 0.7%
5 to 9 units 538 5.1%
10 to 19 units 253 2.4%
20 to 49 units 957 9%
50 or more units 1,590 15%
Mobile home 79 0.7%
Homes built since 2020
165
126.0% year-over-year change

The age of buildings in Mercer Island

In Mercer Island, the median construction year is 1973. About 3.3% of homes were built before the 1940s, with another 7% going up by 1949. Most development happened in the second half of the 20th century. Then, 12.7% of homes were added from 2000 to 2009, 8.7% between 2010 and 2019, and 1.6% are part of the newest wave of development.

Construction year breakdown by decade
Value Percent YoY change
Built in 1939 or earlier 354 3.3% 4.7%
Built between 1940 and 1949 737 7% -12.2%
Built between 1950 and 1959 1,215 11.4% 14.3%
Built between 1960 and 1969 2,506 23.6% 3.8%
Built between 1970 and 1979 1,687 15.9% -3.3%
Built between 1980 and 1989 1,014 9.6% -8.7%
Built between 1990 and 1999 655 6.2% -1.1%
Built between 2000 and 2009 1,350 12.7% 1.1%
Built between 2010 and 2019 926 8.7% 5.8%
Built in 2020 or later 165 1.6% 126.0%
As a renter, knowing when homes were built helps you understand the potential condition and design of rental units. Newer builds may have more contemporary layouts, while older homes can offer character or larger lots, depending on the area.

Mercer Island occupancy rates

Out of the 10,068 occupied housing units in Mercer Island, 67% are owner-occupied, while 33% are lived in by tenants. Meanwhile, 5.1% of all homes on the local market sit vacant.

Occupied housing units
10,068
1.8% year-over-year change
Occupancy breakdown
Renter occupied
3,322
Owner occupied
6,746
Value Percent YoY
change
Renter occupied 3,322 33% -1.2%
Owner occupied 6,746 67% 3.3%
Unoccupied housing units
5.1%
Unoccupied housing units refer to homes that are currently without residents—whether they're waiting for renters or owners, used seasonally, or simply unclaimed. A higher share of empty homes may mean more housing availability, while a low number can reflect a tighter market with more competition. This, along with the renter-vs.-owner mix, helps paint a clearer picture of what types of housing and services are likely to be available in the area.

Mercer Island housing costs

Housing costs in Mercer Island come to a median of $3,063 per month, while tenants specifically pay a median gross rent of $2,502.

Median housing costs per month
$3,063/month
This figure sums up typical monthly housing costs for all households in the area. If you own, it includes mortgage payments in addition to property taxes, insurance and HOA fees. If you rent, it accounts for rent plus extras like utilities. It’s useful for seeing how local living expenses stack up compared to other places.
Median gross rent in Mercer Island
$2,502/month
Gross rent gives a more complete look at what renters actually pay, including not just base rent, but also utilities and fees. It’s a key number for evaluating rental affordability in your area of interest and understanding how it compares to nearby locations.

Education in Mercer Island

Mercer Island education at a glance

About 8.8% of the population in Mercer Island went to high school, while 8.3% pursued college studies. Another 4.6% earned an associate degree and 35.8% hold a bachelor’s. Meanwhile, 41.3% went even further, earning a master’s or doctorate.

Education level
Value Percent YoY change
No high school 218 1.1% -17.4%
High school diploma 1,759 8.8% -0.5%
College diploma 1,657 8.3% -9.8%
Associate degree 915 4.6% -15.0%
Bachelor's degree 7,122 35.8% -3.1%
Graduate degree 8,202 41.3% 10.8%
A community’s education mix can offer insights into the local economy and housing market. Higher levels of education often align with more job opportunities and stable incomes, which can increase demand for homes and influence both rent prices and rental availability.

Income in Mercer Island

How much people earn in Mercer Island

The average annual household income in Mercer Island was $318,528 in 2024, the most recent annual data available, according to the U.S. Census Bureau. This marked a +5% change from the previous year. At the same time, the median income stood at $219,069, reflecting a +8.3% shift over the same period.

Average household income in Mercer Island
$318,528/year
5.0% year-over-year change
Median household income in Mercer Island
$219,069/year
8.3% year-over-year change

Mercer Island income by age

In Mercer Island, households led by residents aged 25 to 44 — usually in the early to mid stages of their careers — have a median income of $230,588. Those with someone between 45 and 64 in charge, often well established professionally, earn $250,001 overall. Younger households, where the main provider is under 25 and just starting out, report a median income of $74,250, while those led by someone over 65, many of whom may be retired, have about $112,679 in earnings. Overall, 96.2% of the locals in this community live above the poverty line.

Income breakdown by age
Value YoY change
Under 25 $74,250 3.5%
25 - 44 $230,588 2.1%
45 - 64 $250,001 0.0%
Over 65 $112,679 -2.4%
Above poverty level
24,038
Below poverty level
957
Value Percent YoY
change
Above poverty level 24,038 96.2% 0.7%
Below poverty level 957 3.8% -16.1%

Average renter income in Mercer Island

To get a better sense of what renters earn on average in Mercer Island, their median household income was $93,658 according to 2022 Census data. In addition, the rent-to-income ratio in the area, at 32.1%, shows what portion of their earnings goes toward housing expenses.

Renter median household income
$93,658
Rent-to-income ratio
32.1%
Understanding the rent-to-income ratio can help renters gauge if local housing costs align with their earnings. A ratio under 30% usually signals affordability, while exceeding this mark means rent is taking a larger-than-recommended bite out of income. That could make it harder for you to cover other costs like transportation, healthcare, or child care.

Employment in Mercer Island

Workforce and job types in Mercer Island

The job market in Mercer Island is powered by 12,219 working residents, spread across a range of industries and roles. 97.1% of the working population are employed in professional or administrative positions, while 2.9% are in hands-on or service-based jobs. Also, 14.4% run their own businesses, 65.7% are employed by private companies, and 10.6% work in the public sector.

Workforce demographics

Working population
12,219
1.4% year-over-year change
White collar
11,865
Blue collar
354
Value Percent YoY change
White collar 11,865 97.1% 1.3%
Blue collar 354 2.9% 5.7%
Employer type
Self employees
14.4%
Private companies
65.7%
Governmental workers
10.6%
Not for profit companies
9.3%
Value Percent YoY change
Self employees 1,764 14.4% -7.2%
Private companies 8,026 65.7% 5.7%
Governmental workers 1,293 10.6% -3.1%
Not for profit companies 1,136 9.3% -6.9%
Unemployment rate
3.0%
26.1% year-over-year change

Available workforce

The unemployment rate in Mercer Island stands at 3%, representing the share of the workforce currently without a job and actively looking for one.

For renters, the unemployment rate helps paint a picture of job security and financial stability in the area. Rates around 4% to 5% are considered typical. A lower-than-average rate might suggest strong job prospects and a thriving local economy, while a higher rate could hint at fewer opportunities—both useful to consider when planning a move.

Transportation in Mercer Island

How people get around in Mercer Island

Commuting methods vary: 55.5% of residents travel by personal vehicle and 1.6% prefer to walk, while the remaining share relies on public transit or on two wheelers to get from A to B.

Means of transportation
Value Percent YoY change
Car 6,672 55.5% -0.1%
Taxicab 7 0.1% 0.0%
Bus or trolleybus 358 3% -34.4%
Subway or elevated 11 0.1% N/A
Bicycle 12 0.1% -33.3%
Walk 190 1.6% -1.6%
Understanding how locals get to work can help you plan your own routine. High car usage might mean you’ll need a vehicle, while strong public transit or walkability could save you the hassle. Commute times also play a big role in quality of life—shorter trips can give you more time for the things you enjoy.

What is the median and average household income in Mercer Island by zipcode?

Zipcode Population Number of households Median income Average income
98040 25,307 10,068 $219,069 $318,528

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FAQs about Mercer Island demographics 

What is the total population of Mercer Island?

Mercer Island has a total population of 25,307 residents, according to the latest release from the U.S. Census Bureau: the 2019-2023 American Community Survey (ACS) 5-year estimates. This figure changed by +0.1% compared to a year ago.

What is the gender ratio in Mercer Island?

The gender ratio in Mercer Island is as follows:
  • 47.6% males (12,056 residents)
  • 52.4% females (13,251 residents)

What is the median age in Mercer Island?

The median age in Mercer Island is 46.4.

What is the age distribution of the population in Mercer Island?

The age distribution in Mercer Island is as follows:
  • Under 15: 15.8% (3,997 residents)
  • Ages 15-24: 12.2% (3,080 residents)
  • Ages 25-44: 20.3% (5,147 residents)
  • Ages 45-64: 29.5% (7,473 residents)
  • Over 65: 22.2% (5,610 residents)

What is the racial and ethnic makeup of Mercer Island?

The racial and ethnic makeup of Mercer Island is as follows:
  • White: 63.6% (16,085 residents)
  • Black or African American: 0.9% (234 residents)
  • American Indian and Alaska Native: 0% (6 residents)
  • Asian: 24.5% (6,205 residents)
  • Native Hawaiian and Other Pacific Islander: 0% (0 residents)
  • Two or More Races: 10.1% (2,560 residents)
  • Other: 0.9% (217 residents)

What percentage of the population in Mercer Island are U.S.-born citizens?

U.S.-born citizens represent 71.8% of the population in Mercer Island.

How many housing units are there in Mercer Island?

There are 10,609 housing units in Mercer Island, reflecting a +1.5% change compared to the previous year, according to the latest data from the U.S. Census Bureau.

How many households are in Mercer Island and what is the average household size?

Mercer Island has a total of 10,068 households, with an average of 2 people in each.

What is the median household income in Mercer Island?

Mercer Island has a median household income of $219,069, representing a +8.3% shift from the previous year, according to the U.S. Census Bureau.

What is the employment rate and job market overview for Mercer Island?

The employment rate is 97% in Mercer Island, with a workforce of 12,219 residents. Here’s a detailed breakdown of the local job market:

Job types:
  • White-collar workers: 97.1% (11,865 residents)
  • Blue-collar workers: 2.9% (354 residents)

Places of employment:
  • Self-employed: 14.4% (1,764 residents)
  • Private companies: 65.7% (8,026 residents)
  • Governmental workers: 10.6% (1,293 residents)
  • Not-for-profit companies: 9.3% (1,136 residents)

Data source & methodology

The demographic data on this page was sourced from the latest U.S. Census Bureau release—the 2019–2023 American Community Survey (ACS) 5-year estimates.

The information, issued annually, is compiled and published by the Point2Homes Research Team as soon as new data becomes available.

No representation, guarantee, or warranty is made concerning the accuracy or completeness of modified or aggregated information for particular areas.

Page last updated: September 2025