According to the 2011 Census of India, Marai Kalan (location code 368579) had a total population of 10,447, of which 5,402 (52%) were males and 5,045 (48%) were females.

The total number of literate persons in Marai Kalan was 7,230 (81.47% of the population over 6 years).

[1] According to the District Census Handbook 2011, Hazaribagh, Marai Kalan covered an area of 2.77 km2.

Among the civic amenities, it had 7 km roads with open drains, the protected water supply involved uncovered wells, hand pumps.

It had 1,476 domestic electric connections, 14 road lighting points.