It is not known exactly how many people died during the period of the famine, although it is believed that more died from disease than from starvation.
State registration of births, marriages, or deaths had not yet begun, and records kept by the Roman Catholic Church are incomplete.
One possible estimate has been reached by comparing the expected population with the eventual numbers in the 1850s.
A census taken in 1841 recorded a population of 8,175,124.
A census immediately after the famine in 1851 counted 6,552,385, a drop of over 1.5 million in 10 years.
The census commissioners estimated that, at the normal rate of population increase, the population in 1851 should have grown to just over 9 million if the famine had not occurred.

On the in-development Great Irish Famine Online resource, produced by the Geography department of University College Cork, the population of Ireland section states, that together with the census figures being called low, before the famine it reads that "it is now generally believed" that over 8.75 million people populated the island of Ireland prior to it striking.

In 1851, the census commissioners collected information on the number who died in each family since 1841, and the cause, season, and year of death.
They recorded 21,770 total deaths from starvation in the previous decade, and 400,720 deaths from disease.
Listed diseases were fever, diphtheria, dysentery, cholera, smallpox, and influenza, with the first two being the main killers (222,021 and 93,232).
The commissioners acknowledged that their figures were incomplete and that the true number of deaths was probably higher:
The greater the amount of destitution of mortality ... the less will be the amount of recorded deaths derived through any household form;—for not only were whole families swept away by disease ... but whole villages were effaced from off the land.

Later historians agree that the 1851 death tables "were flawed and probably under-estimated the level of mortality".
The combination of institutional and figures provided by individuals gives "an incomplete and biased count" of fatalities during the famine.

Cormac Ó Gráda, referencing the work of W. A. MacArthur, writes that specialists have long known that the Irish death tables were inaccurate.
As a result, Ó Gráda says that the tables undercount the number of deaths, because information was gathered from surviving householders having to look back over the previous 10 years, and death and emigration had cleared away entire families, leaving few or no survivors to answer the census questions.

S. H. Cousens' estimate of 800,000 deaths relied heavily on retrospective information contained in the 1851 census and elsewhere, and is now regarded as too low.
Modern historian Joseph Lee says "at least 800,000", and R. F. Foster estimates that "at least 775,000 died, mostly through disease, including cholera in the latter stages of the holocaust".
He further notes that "a recent sophisticated computation estimates excess deaths from 1846 to 1851 as between 1,000,000 and 1,500,000 ... after a careful critique of this, other statisticians arrive at a figure of 1,000,000".

Joel Mokyr's estimates at an aggregated county level range from 1.1 million to 1.5 million deaths between 1846 and 1851.
Mokyr produced two sets of data which contained an upper-bound and lower-bound estimate, which showed not much difference in regional patterns.
The true figure is likely to lie between the two extremes of half and one and a half million, and the most widely accepted estimate is one million.

At least a million people are thought to have emigrated as a result of the famine.
There were about 1 million long-distance emigrants between 1846 and 1851, mainly to North America.
The total given in the 1851 census is 967,908.
Short-distance emigrants, mainly to Britain, may have numbered 200,000 or more.

Another area of uncertainty lies in the descriptions of disease given by tenants as to the cause of their relatives' deaths.
Though the 1851 census has been rightly criticised as underestimating the true e
It is not known exactly how many people died during the period of the famine, although it is believed that more died from disease than from starvation. State registration of births, marriages, or deaths had not yet begun, and records kept by the Roman Catholic Church are incomplete. One possible estimate has been reached by comparing the expected population with the eventual numbers in the 1850s. A census taken in 1841 recorded a population of 8,175,124. A census immediately after the famine in 1851 counted 6,552,385, a drop of over 1.5 million in 10 years. The census commissioners estimated that, at the normal rate of population increase, the population in 1851 should have grown to just over 9 million if the famine had not occurred.
On the in-development Great Irish Famine Online resource, produced by the Geography department of University College Cork, the population of Ireland section states, that together with the census figures being called low, before the famine it reads that "it is now generally believed" that over 8.75 million people populated the island of Ireland prior to it striking.
In 1851, the census commissioners collected information on the number who died in each family since 1841, and the cause, season, and year of death. They recorded 21,770 total deaths from starvation in the previous decade, and 400,720 deaths from disease. Listed diseases were fever, diphtheria, dysentery, cholera, smallpox, and influenza, with the first two being the main killers (222,021 and 93,232). The commissioners acknowledged that their figures were incomplete and that the true number of deaths was probably higher:
The greater the amount of destitution of mortality ... the less will be the amount of recorded deaths derived through any household form;—for not only were whole families swept away by disease ... but whole villages were effaced from off the land.
Later historians agree that the 1851 death tables "were flawed and probably under-estimated the level of mortality". The combination of institutional and figures provided by individuals gives "an incomplete and biased count" of fatalities during the famine.
Cormac Ó Gráda, referencing the work of W. A. MacArthur, writes that specialists have long known that the Irish death tables were inaccurate. As a result, Ó Gráda says that the tables undercount the number of deaths, because information was gathered from surviving householders having to look back over the previous 10 years, and death and emigration had cleared away entire families, leaving few or no survivors to answer the census questions.
S. H. Cousens' estimate of 800,000 deaths relied heavily on retrospective information contained in the 1851 census and elsewhere, and is now regarded as too low. Modern historian Joseph Lee says "at least 800,000", and R. F. Foster estimates that "at least 775,000 died, mostly through disease, including cholera in the latter stages of the holocaust". He further notes that "a recent sophisticated computation estimates excess deaths from 1846 to 1851 as between 1,000,000 and 1,500,000 ... after a careful critique of this, other statisticians arrive at a figure of 1,000,000".
Joel Mokyr's estimates at an aggregated county level range from 1.1 million to 1.5 million deaths between 1846 and 1851. Mokyr produced two sets of data which contained an upper-bound and lower-bound estimate, which showed not much difference in regional patterns. The true figure is likely to lie between the two extremes of half and one and a half million, and the most widely accepted estimate is one million.
At least a million people are thought to have emigrated as a result of the famine. There were about 1 million long-distance emigrants between 1846 and 1851, mainly to North America. The total given in the 1851 census is 967,908. Short-distance emigrants, mainly to Britain, may have numbered 200,000 or more.
Another area of uncertainty lies in the descriptions of disease given by tenants as to the cause of their relatives' deaths. Though the 1851 census has been rightly criticised as underestimating the true e
Great Famine (Ireland)