2000
#10,920
National surname rank
Recorded bearers 2,674
First available Census row
Per 100,000 0.99
Rare Last name
Blau
A German and Jewish surname derived from the Middle High German word "blā" or "blāo," meaning "blue."
According to the 2020 US Census Bureau surname tables, roughly 3,330 Americans carry the last name Blau. That puts it at #10,534 in the national surname ranking, appearing at a frequency of 0.97 per 100,000 people (about 1 in 102,929 residents).
This page is the full Name Census profile for the Blau 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.
Bearers in the US
3.3K
1 in 102,929
Census rank
#10,534
2020 decennial data
Per 100,000
1.0
Frequency rate
Recorded bearers
2.9K
rare in the US
Popularity narrative
The Census Bureau recorded 2,904 bearers of the surname Blau in its 2020 decennial surname file. At a rate of 0.97 per 100,000 residents, it holds the 10534th position in the national surname ranking.
Among Census respondents with the surname Blau, the largest self-reported group is White at 93.6%. The next largest groups are Hispanic (3.3%) and Two or More Races (1.4%).
Origin
Meaning and origin of Blau
The surname "BLAU" is of German origin, derived from the German word "blau," meaning "blue." It is believed to have originated in the Middle Ages, around the 13th or 14th century, and was likely used as a descriptive name for someone with blue eyes or who frequently wore blue clothing.
One of the earliest recorded instances of the surname "BLAU" can be found in the Codex Diplomaticus Saxoniae Regiae, a collection of historical documents from the region of Saxony, dated around the 14th century. The name is also mentioned in several medieval records and manuscripts from various parts of Germany.
The surname "BLAU" is closely associated with several prominent figures throughout history. One notable example is Johann Blau (1590-1648), a German composer and organist who served as the court composer for the Elector of Saxony. Another noteworthy individual is Johann Leonhard Blau (1696-1776), a German architect and master builder who designed several notable buildings in the Baroque style.
In the 19th century, Johann Blau (1805-1883) gained recognition as a German chemist and pharmacist, known for his contributions to the field of analytical chemistry. Additionally, Carl Blau (1834-1906) was a German philologist and linguist who specialized in the study of Semitic languages.
One of the most famous individuals with the surname "BLAU" is the Austrian writer and journalist Max Blau (1884-1944), who was a prominent figure in the literary circles of Vienna during the early 20th century. His works often explored themes of social injustice and the struggles of the working class.
While the surname "BLAU" has its roots in Germany, it has since spread to various parts of the world, including other European countries, as well as North America and beyond, carried by individuals of German descent or through immigration.
Demographics
Ancestry and ethnicity for Blau
Among Census respondents with the surname Blau, the largest self-reported group is White at 93.6%. The next largest groups are Hispanic (3.3%) and Two or More Races (1.4%).
The bar chart below shows how Blau 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 Blau surname at the time of the 2020 Census, not any inherent property of the name itself.
- White93.6% · 2,717
- Hispanic or Latino3.3% · 96
- Two or more races1.4% · 42
- Asian and Pacific Islander1.0% · 30
- Black or African American0.6% · 16
- American Indian and Alaska Native0.1% · 3
Timeline
Historical Census data for Blau
Blau 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
#10,758
National surname rank
Recorded bearers 2,965
+291 bearers (+10.9%)
Per 100,000 1.01
Rank movement Up 162 places
2020
#10,534
National surname rank
Recorded bearers 2,904
-61 bearers (-2.1%)
Per 100,000 0.97
Rank movement Up 224 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #10,920 | 2,674 | 0.99 | First available Census row | First available Census row |
| 2010 | #10,758 | 2,965 | 1.01 | +291 bearers (+10.9%) | Up 162 places |
| 2020 | #10,534 | 2,904 | 0.97 | -61 bearers (-2.1%) | Up 224 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 Blau 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 | #10,758 | #10,534 | 2.1% |
| Count | 2,965 | 2,904 | -2.1% |
| Per 100K | 1.01 | 0.97 | -3.8% |
Between the 2010 and 2020 Census, the number of Blau bearers went from 2,965 to 2,904 (-2.1% change). The surname moved up 224 positions in the national ranking, going from #10,758 to #10,534.
FAQ
Blau surname: questions and answers
How many people in the U.S. have the surname Blau?
Name Census estimates that about 3,330 living Americans carry the surname Blau. Using the current population baseline, that works out to roughly 1 in 102,929 residents.
How common is Blau?
Blau ranks #10,534 in the 2020 Census surname tables and is classified on this site as "Rare." The Census recorded the name at a frequency of 0.97 per 100,000 residents, which is about 1 people out of every 100,000.
How many people with this surname were counted in the Census?
The raw 2020 Census file counted 2,904 people with the surname Blau. That is different from the site's living-bearer estimate (3,330), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 0.97 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 0.97 per 100,000 means that if you picked a random group of 100,000 U.S. residents, you would expect about 1 of them to have the surname Blau.
Has Blau become more or less common over time?
Between 2010 and 2020, the surname Blau went from 2,965 recorded bearers to 2,904. That is a decrease of 61 (-2.1%). In the national ranking it rose from #10,758 to #10,534.
What does the Census say about the background of Blau?
Among Census respondents with the surname Blau, the largest self-reported group is White at 93.6%. The next largest groups are Hispanic (3.3%) and Two or More Races (1.4%). 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 Blau in the 2020 Census, accounting for 93.6% (2,717 people in the source table).
What is the full ancestry breakdown?
Blau appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (93.6%), Hispanic (3.3%), Two or More Races (1.4%). 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 Blau (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 Blau mean?
A German and Jewish surname derived from the Middle High German word "blā" or "blāo," meaning "blue." 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 Blau (0.97 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 people share the surname Blau?
For a faster, more casual read, check HowManyOfMe.org — our sister site built around that single question.