Boncourt has a population (as of December 2018) of 1,225.
 As of 2008, 6.5% of the population are resident foreign nationals.
 Over the last 10 years (2000–2010) the population has changed at a rate of -2.6%.
 Migration accounted for 2%, while births and deaths accounted for -4.3%.

Most of the population (as of 2000) speaks French (1,312 or 96.6%) as their first language, German is the second most common (29 or 2.1%) and Italian is the third (6 or 0.4%).
 There is 1 person who speaks Romansh.

As of 2008, the population was 47.6% male and 52.4% female.
 The population was made up of 573 Swiss men (44.1% of the population) and 45 (3.5%) non-Swiss men.
 There were 639 Swiss women (49.2%) and 41 (3.2%) non-Swiss women.
 Of the population in the municipality, 530 or about 39.0% were born in Boncourt and lived there in 2000.
 There were 468 or 34.5% who were born in the same canton, while 134 or 9.9% were born somewhere else in Switzerland, and 164 or 12.1% were born outside of Switzerland.

As of 2000, children and teenagers (0–19 years old) make up 19.5% of the population, while adults (20–64 years old) make up 55.8% and seniors (over 64 years old) make up 24.7%.

As of 2000, there were 475 people who were single and never married in the municipality.
 There were 685 married individuals, 145 widows or widowers and 53 individuals who are divorced.

As of 2000, there were 560 private households in the municipality, and an average of 2.3 persons per household.
 There were 179 households that consist of only one person and 29 households with five or more people.
 In 2000, a total of 549 apartments (90.9% of the total) were permanently occupied, while 27 apartments (4.5%) were seasonally occupied and 28 apartments (4.6%) were empty.
 As of 2009, the construction rate of new housing units was 1.5 new units per 1000 residents.
 The vacancy rate for the municipality, in 2010, was 3.63%.

The historical population is given in the following chart:
Boncourt has a population (as of December 2018) of 1,225.  As of 2008, 6.5% of the population are resident foreign nationals.  Over the last 10 years (2000–2010) the population has changed at a rate of -2.6%.  Migration accounted for 2%, while births and deaths accounted for -4.3%.
Most of the population (as of 2000) speaks French (1,312 or 96.6%) as their first language, German is the second most common (29 or 2.1%) and Italian is the third (6 or 0.4%).  There is 1 person who speaks Romansh.
As of 2008, the population was 47.6% male and 52.4% female.  The population was made up of 573 Swiss men (44.1% of the population) and 45 (3.5%) non-Swiss men.  There were 639 Swiss women (49.2%) and 41 (3.2%) non-Swiss women.  Of the population in the municipality, 530 or about 39.0% were born in Boncourt and lived there in 2000.  There were 468 or 34.5% who were born in the same canton, while 134 or 9.9% were born somewhere else in Switzerland, and 164 or 12.1% were born outside of Switzerland.
As of 2000, children and teenagers (0–19 years old) make up 19.5% of the population, while adults (20–64 years old) make up 55.8% and seniors (over 64 years old) make up 24.7%.
As of 2000, there were 475 people who were single and never married in the municipality.  There were 685 married individuals, 145 widows or widowers and 53 individuals who are divorced.
As of 2000, there were 560 private households in the municipality, and an average of 2.3 persons per household.  There were 179 households that consist of only one person and 29 households with five or more people.  In 2000, a total of 549 apartments (90.9% of the total) were permanently occupied, while 27 apartments (4.5%) were seasonally occupied and 28 apartments (4.6%) were empty.  As of 2009, the construction rate of new housing units was 1.5 new units per 1000 residents.  The vacancy rate for the municipality, in 2010, was 3.63%.
The historical population is given in the following chart:
Boncourt, Switzerland