After receiving a military education, Everest joined the East India Company and arrived in India at the age of 16. He was eventually made an assistant to William Lambton on the Great Trigonometric Survey, and replaced Lambton as superintendent of the survey in 1823. Everest was largely responsible for surveying the meridian arc from the southernmost point of India north to Nepal, a distance of about 2,400 kilometres (1,500 mi), a task which took from 1806 to 1841 to complete. He was made Surveyor General of India in 1830, retiring in 1843 and returning to England.
In 1865, the Royal Geographical Society renamed Peak XV – at the time only recently identified as the world's highest peak – in Everest's honour. Andrew Scott Waugh, his protégé and successor as surveyor general, had been responsible for putting his name forward in 1856. Everest's name was used as a compromise due to the difficulty of choosing between multiple local names for the mountain. He initially objected to the honour, as he had had nothing to do with its discovery and believed his name was not easily written or pronounced in Hindi.
Everest was born on 4 July 1790, but the location of his birthplace is uncertain. He was baptised at St Alfege Church, Greenwich, London, on 27 January 1791. He was either born at Greenwich or at Gwernvale Manor, his family's estate near Crickhowell, Brecknockshire, Wales. Everest was the eldest son and third of six children born to Lucetta Mary (née Smith) and William Tristram Everest. His father was a solicitor and justice of the peace, part of a "Greenwich family of long standing", and was successful enough to acquire a large estate in South Wales. His grandfather John Everest, the son of a butcher, was the first in the family to enter the legal profession. The Everest family in Greenwich can be traced at least as far back as the late 1600s, when Tristram Everest – John's great-grandfather – was a butcher in Church Street.
Everest was educated at the Royal Military College, Sandhurst, and the Royal Military Academy, Woolwich, before joining the East India Company as a cadet in 1806. He was commissioned as a second lieutenant in the Bengal Artillery, and sailed for India the same year.