Demographics of Bihar
According to the 2023 Bihar Caste Census, Bihar had a total population of 130,725,310, nearly 89% of it rural. It was also India's most densely populated state, with 1,388 persons per square kilometre. 82% of Bihar's population practiced Hinduism, while 17.7% followed Islam.
As of 2011, the sex ratio was 918 females per 1000 males. Almost 58% of Bihar's population was below 25 years age, which is the highest in India. At 11.3%, Bihar has the second-lowest urbanisation rate in India after Himachal Pradesh.
Most of Bihar's population belongs to a collection of ethnic groups speaking indic languages, the most prominent ones being Bhojpuri, Maithili and Magahi. It also attracted Punjabi Hindu refugees during the Partition of British India in 1947. Bihar has a total literacy rate of List of [Indian states and union territories by literacy rate|70.70%], recording a growth of 20% in female literacy over the preceding decade. According to the 2011 census, 82.7% of Bihar's population practised Hinduism, while 16.9% followed Islam. As of 2021, Bihar has highest fertility rate of 3.41 in comparison to the other states of India.
Population
| Age Group | Total | Male | Female |
| 0–4 | 11,006,072 | 5,623,280 | 5,382,792 |
| 5–9 | 12,804,302 | 6,705,263 | 6,099,039 |
| 10–14 | 11,063,777 | 5,970,201 | 5,093,576 |
| 15–19 | 7,190,188 | 4,028,643 | 3,161,545 |
| 20–24 | 6,323,193 | 3,180,063 | 3,143,130 |
| 25–29 | 5,908,308 | 2,894,706 | 3,013,602 |
| 30–34 | 5,549,787 | 2,713,871 | 2,835,916 |
| 35–39 | 5,077,935 | 2,576,089 | 2,501,846 |
| 40–44 | 4,153,203 | 2,213,770 | 1,939,433 |
| 45–49 | 3,461,664 | 1,778,368 | 1,683,296 |
| 50–54 | 2,711,041 | 1,543,620 | 1,167,421 |
| 55–59 | 2,069,940 | 990,011 | 1,079,929 |
| 60–64 | 2,103,909 | 1,120,743 | 983,166 |
| 65–69 | 1,354,937 | 683,656 | 671,281 |
| 70–74 | 1,029,921 | 571,438 | 458,483 |
| 75–79 | 446,860 | 233,961 | 212,899 |
| 80+ | 565,647 | 312,207 | 253,440 |
| Age not stated | 177,825 | 103,905 | 73,920 |
| All ages | 82,998,509 | 43,243,795 | 39,754,714 |
Religion
As per recently released Bihar caste-based survey 2022, Hinduism is practised by 81.99% and Islam is followed by 17.70%.Caste and ethnic groups
As per Bihar government’s Bihar caste-based survey 2022 report, released on 2 October 2023, showed that extremely backward classes account for 36.01 percent of the 13.07 crore population of the state. BCs, EBCs together account for 63% of total population of Bihar.| Caste | Population | Percentage |
| Yadav | - | |
| Kushwaha | - | |
| Kurmi | - | |
| Brahmin | - | |
| Teli | - | |
| Mallah | - | |
| Nonia | - | |
| Kanu | - | |
| Bania | - | |
| Bhumihar | - | |
| Rajput | - | |
| Dushadh | - | |
| Musahar | - | |
| Kayastha | - | |
| Ravidas | - | |
| Tanti | - | |
| Nai | - |
- As per, 2011 Census of India, Scheduled Castes constitute 16% of Bihar's 104 million population. The census identified 21 of 23 Dalit sub-castes as Mahadalits. Mahadalit community consists of the following sub castes - Bantar, Bauri, Bhogta, Bhuiya, Chaupal, Dabgar, Dom, Ghasi, Halalkhor, Hari, Kanjar, Kurariar, Lalbegi, Musahar, Nat, Pan, Rajwar, Turi, Dhobi, Pasi, Chamar and Paswan. Paswan caste was initially left out of the Mahadalit category. Adivasis constitute around 1.3% of Bihar population. Tribals include Gond, Santhal and Tharu communities in Bihar.
- Extremely Backward Class are also sometimes referred to as Most Backward Class. There are 130-odd EBC castes in Bihar.
Languages
Maithili language is the only language of Bihar which is one of the 22 Scheduled language of India.
Bhojpuri, Magahi, and Surjapuri are counted under Hindi. Proponents have called for Bhojpuri, Magahi, Bajjika and Angika to receive the same status.
Education
| Level | Persons | Male | Female |
| Literate without educational | 1,715,049 | 1,109,731 | 605,318 |
| Below Primary | 7,890,329 | 4,754,137 | 3,136,192 |
| Primary | 8,334,709 | 5,130,917 | 3,203,792 |
| Middle | 4,390,226 | 3,012,151 | 1,378,075 |
| Secondary | 4,751,560 | 3,439,918 | 1,311,642 |
| Higher Secondary | 1,826,093 | 1,385,282 | 440,811 |
| Technical Diploma | 24,989 | 20,088 | 4,901 |
| Non-technical Diploma | 48,532 | 40,458 | 8,074 |
| Graduate & above | 2,109,415 | 1,737,651 | 371,764 |
| Unclassified | 18,675 | 14,043 | 4,632 |
Bihar has a total literacy rate of 70.9%. Overall Male and Female literacy rate is 79.7% and 60.5% respectively. Total Rural literacy rate is 43.9%. In rural areas of Bihar, Male and Female literacy rate is 57.1 and 29.6 respectively. Total Urban literacy rate is 71.9. In urban areas of Bihar, Male and Female literacy rate is 79.9 and 62.6 respectively.
Total number of literates in Bihar is 3,16,75,607 which consists 2,09,78,955 Male and 1,06,96,652 Female.
Patna has highest Literacy Rate of 63.82% followed by Rohtas and Munger.
Kishanganj has lowest Literacy Rate of 31.02% followed by Araria and Katihar.