2000
#5,226
National surname rank
Recorded bearers 6,137
First available Census row
Per 100,000 2.27
Rare Last name
Koster
A Dutch occupational surname referring to a sexton or church custodian.
According to the 2020 US Census Bureau surname tables, roughly 6,581 Americans carry the last name Koster. That puts it at #5,808 in the national surname ranking, appearing at a frequency of 1.92 per 100,000 people (about 1 in 52,082 residents).
This page is the full Name Census profile for the Koster surname. You will find the Census Bureau frequency data, a multi-census history view, an ancestry and ethnicity breakdown based on self-reported demographics, the name's meaning and origin where available, and answers to the most common questions people ask about this surname.
For British records, Name Census UK has a British surname profile for Koster with 1881 census detail, origin facts and modern UK distribution where available.
Bearers in the US
6.6K
1 in 52,082
Census rank
#5,808
2020 decennial data
Per 100,000
1.9
Frequency rate
Recorded bearers
5.7K
rare in the US
Popularity narrative
The Census Bureau recorded 5,739 bearers of the surname Koster in its 2020 decennial surname file. At a rate of 1.92 per 100,000 residents, it holds the 5808th position in the national surname ranking.
Among Census respondents with the surname Koster, the largest self-reported group is White at 92.8%. The next largest groups are Hispanic (3.3%) and Two or More Races (2.2%).
Origin
Meaning and origin of Koster
The surname Koster is of Dutch origin, originating from the Low Countries region of northwestern Europe in the 16th century. It is derived from the Dutch word 'koster', which means 'sexton' or 'parish clerk'. The name was initially given to individuals who held this occupation, responsible for maintaining church buildings and ringing the bells.
One of the earliest recorded mentions of the name Koster can be found in the Dutch records of the city of Leiden in the late 1500s. A certain Jan Koster was listed as a resident of the city during this time period. Another early record comes from the Dutch province of Friesland, where a Pieter Koster was documented in the town of Harlingen in the early 1600s.
The surname Koster has also been associated with various place names in the Netherlands, such as Kosterswolde and Kosterburen, suggesting that some individuals may have adopted the name based on their place of residence or origin.
A notable individual with the surname Koster was Laurens Janszoon Koster, who lived in the Dutch town of Haarlem from around 1420 to 1440. He is often credited as one of the earliest pioneers of movable type printing in Europe, predating Johannes Gutenberg.
Another prominent figure was Samuel Koster, a Dutch naval officer and explorer who lived from 1579 to 1668. He made significant contributions to the exploration and mapping of the West Indies and South America during his time with the Dutch West India Company.
In the realm of art, Jan Koster (1644-1718) was a Dutch Golden Age painter known for his still life paintings and portraits. He spent most of his career in the city of Amsterdam.
Moving into the 19th century, Theodoor Koster (1818-1892) was a Dutch theologian and writer who served as a pastor in the Netherlands Reformed Church. He authored several works on religious subjects and was also involved in the translation of the Bible into Dutch.
Lastly, Cornelis Koster (1892-1953) was a Dutch architect and urban planner who played a significant role in the reconstruction and development of Rotterdam after World War II. His designs for residential neighborhoods and public buildings helped shape the modern cityscape of Rotterdam in the post-war era.
Demographics
Ancestry and ethnicity for Koster
Among Census respondents with the surname Koster, the largest self-reported group is White at 92.8%. The next largest groups are Hispanic (3.3%) and Two or More Races (2.2%).
The bar chart below shows how Koster bearers described their own race and ethnicity on the 2020 Census form. The Census Bureau groups responses into six broad categories: White, Black or African American, Hispanic or Latino, Asian and Pacific Islander, American Indian and Alaska Native, and Two or More Races. When a category has too few respondents for a given surname, the Bureau suppresses the figure to protect individual privacy, which is why some names show fewer than six slices.
Percentages are shown for every Census year so the breakdown stays comparable over time. When the source file also includes raw headcounts, Name Census shows those alongside the percentages in the legend.
Keep in mind that these are self-reported numbers. A person's surname does not determine their race or ethnicity, and the distribution you see here reflects the specific population who happened to carry the Koster surname at the time of the 2020 Census, not any inherent property of the name itself.
- White92.8% · 5,323
- Hispanic or Latino3.3% · 188
- Two or more races2.2% · 129
- Asian and Pacific Islander0.6% · 36
- American Indian and Alaska Native0.6% · 35
- Black or African American0.5% · 28
Timeline
Historical Census data for Koster
Koster appears in 3 published Census surname files: 2000, 2010, 2020. The cards below show how the name's rank and bearer count changed across each release.
2010
#5,293
National surname rank
Recorded bearers 6,580
+443 bearers (+7.2%)
Per 100,000 2.23
Rank movement Down 67 places
2020
#5,808
National surname rank
Recorded bearers 5,739
-841 bearers (-12.8%)
Per 100,000 1.92
Rank movement Down 515 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #5,226 | 6,137 | 2.27 | First available Census row | First available Census row |
| 2010 | #5,293 | 6,580 | 2.23 | +443 bearers (+7.2%) | Down 67 places |
| 2020 | #5,808 | 5,739 | 1.92 | -841 bearers (-12.8%) | Down 515 places |
For 2020, the Census Bureau published race and Hispanic-origin columns as counts rather than percentages. Name Census converts those counts back into shares so the ancestry section stays comparable with the older surname files.
Year on year
2010 vs 2020 Census
How has the Koster surname changed between Census years? The chart shows bearer count side by side, and the table compares rank, count, and frequency.
Census year comparison
20102020
| Metric | 2010 | 2020 | Change |
|---|---|---|---|
| Rank | #5,293 | #5,808 | -9.7% |
| Count | 6,580 | 5,739 | -12.8% |
| Per 100K | 2.23 | 1.92 | -13.9% |
Between the 2010 and 2020 Census, the number of Koster bearers went from 6,580 to 5,739 (-12.8% change). The surname moved down 515 positions in the national ranking, going from #5,293 to #5,808.
FAQ
Koster surname: questions and answers
How many people in the U.S. have the surname Koster?
Name Census estimates that about 6,581 living Americans carry the surname Koster. Using the current population baseline, that works out to roughly 1 in 52,082 residents.
How common is Koster?
Koster ranks #5,808 in the 2020 Census surname tables and is classified on this site as "Rare." The Census recorded the name at a frequency of 1.92 per 100,000 residents, which is about 2 people out of every 100,000.
How many people with this surname were counted in the Census?
The raw 2020 Census file counted 5,739 people with the surname Koster. That is different from the site's living-bearer estimate (6,581), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 1.92 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 1.92 per 100,000 means that if you picked a random group of 100,000 U.S. residents, you would expect about 2 of them to have the surname Koster.
Has Koster become more or less common over time?
Between 2010 and 2020, the surname Koster went from 6,580 recorded bearers to 5,739. That is a decrease of 841 (-12.8%). In the national ranking it fell from #5,293 to #5,808.
What does the Census say about the background of Koster?
Among Census respondents with the surname Koster, the largest self-reported group is White at 92.8%. The next largest groups are Hispanic (3.3%) and Two or More Races (2.2%). These figures come from the 2020 Census Bureau surname tables, based on how respondents described their own race and ethnicity.
Which group reports this surname most often?
White is the largest self-reported group for the surname Koster in the 2020 Census, accounting for 92.8% (5,323 people in the source table).
What is the full ancestry breakdown?
Koster appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (92.8%), Hispanic (3.3%), Two or More Races (2.2%). For 2020, the source file also published raw headcounts for each group, which is why this page can show both percentages and counts in the ancestry section.
Is this page using the latest Census data?
Yes. This page is using the latest surname file currently loaded on Name Census, which is 2020. The historical section above also keeps any older Census surname entries we have for Koster (2000, 2010, 2020).
Does the Census include every surname?
No. The Census Bureau only publishes surnames that appeared at least 100 times in a given decennial Census. That means very rare surnames are excluded entirely, and a surname can appear in one Census release but disappear from a later one if it falls below the reporting threshold.
Why don't the ancestry percentages always add up to exactly 100%?
There are two main reasons: rounding and suppression. The Census Bureau rounds published values, and it may suppress very small cells to protect privacy. For 2020, the Bureau also published raw group counts rather than direct percentages, so Name Census converts those counts back into shares for comparability across census years.
What does Koster mean?
A Dutch occupational surname referring to a sexton or church custodian. The fuller origin note on this page goes into more detail.
Where does the surname data come from?
All surname statistics on Name Census are drawn from the US Census Bureau's decennial surname frequency tables. These files list every surname that appeared 100 or more times in the 2020 Census, along with a count, a per-100,000 rate, and a self-reported demographic breakdown. You can read the full explanation on our methodology page.
How does Name Census estimate living bearers?
For surnames, Name Census does not age cohorts the way it does for first names. Instead, it takes the Census Bureau's published frequency for Koster (1.92 per 100,000) and applies that rate to the current U.S. resident population to estimate how many living Americans have the surname today.
How many Americans have the surname Koster?
For a quick modern estimate, our sister site HowManyOfMe.org answers that in one glance, with the living-bearer count front and centre.