240-300 Trillion Pounds:What could have been the total wealth that was drained out of India during the British rule?

3.9 Million Pounds paid by Mir Jafar to East India Company 1757
230000 pounds per annum from Mir Jafar’s Successor
Annual takling 1932900 pounds from Bengal Bihar and Orissa
Annual revenue from Bihar alone: 680000 pounds
Famine 1770 : 10 million dead, directly due to British policies
Annual revenue from Bengal from 1793: 2.68 million pounds
Famines in 1783, 1792, 1807, 1813, 1823, 1834 and 1854
Famines in 1877, 1878, 1889, 1892, 1897, 1900 : 15 million dead. Note how the incidence of famine has increased with the passage of colonial rule…
https://youtu.be/uV1Ph2FBQZA 
Revenue from Allahabad: Pounds 1682306 per annum circa 1800s
Land Tax: 50% of produce
Maratha area: annual revenue 1,500,000 pounds per annum  circa 1800s
Indian Debt: pounds 51,000,000 in 1857
Indian Debt: pounds 97,000,000 in 1862
Indian Debt pounds 200,000,000 in 1901
44 Million sterling annual outflow from India to Britain. Multiply this figure alone by around 150 – that is approximate 6600 Million – 6.6 Billion. Now compound by 8%… the number comes to 37 Trillion pounds – or nearly 73 Trillion Dollars. India’s external debt as on March 2011 was 345.8 Billion Dollars.  . (This last bit – the compounding and the extrapolation of annual revenues over 150 years is my guesstimate; to equal it out I have used a factor 112 years)
Just one years revenue earnings to the British amount to 243 Billion Sterling- nearly 480 Billion Dollars even when I compound it by just 8%….. more than our total external debt . Just one years takings…
Now just compound the 1.5 Million taking in 1757 for 245 years at 8% – and you get a jaw-dropping number of 232 Trillion Sterling – or 475 Trillion Dollars.

Oh a trick question – “Money”, very little as even what was collected in taxes was largely kept / spent in India, by the EIC agents, Army (~ 40% of tax revenue), or spent on local works (~ £400,000,000 between 1870-1930), rents, goods, bribes, Churches and the like. The local coinage had little value outside of the region it was collected in. If you turned up in Britain with a pocket full of: Bengal: Rupees, Anna, pice, pie; Madras: Pagodas, Fanams, Cash;Canton Tales, Bengkulu dollars; Bombay: Rupees, anna, pice, paisa;Mocha dollars, Travancore: Fanams….. your options for spending / exchanging them would be rather limited, so the “Money” largely stayed in the region of India it was minted in, though a few coins can be found in a number of British museums and collections. As to how much was robbed, the perpetrator not identified and taken out the country, I’d say virtually none, as any smart thief would convert the money into something exchangeable outside of the sub-continent.

FYI: The value of the goods TRADED from / to India is well documented and publicly available eg.

East India Company: Trade and Domestic Financial Statistics, 1755-1838

and there have been numerous books and papers that attempt to estimate net flows over the period, but typically they give conclusions along the lines of:

research suggests that from about 1870 to 1930 Britain took about 1% of India’s wealth per year.

The National Archives – British Empire – India – EIC – 1814-35 – Cloth trade

Alternatively if you take simplistic / theoretical / populist approach you’ll get an answer along the following lines:

• In 1700: India’s population has been estimated at 165 million (27% of The World’s), with a GDP of $90.75 bn (22.6% of The World’s), or $550 per capita (92% of China’s).
• In 1947: India’s population (before partition) was approximately 415 million (17.3%of The World’s), with a GDP $258.164 bn (5% of The World’s), or $622 per capita (130% of China’s).
• In 2008: India + Bangladesh + Pakistan had a combined population around 1.621 billion (22% of The World’s), with a GDP of $3,979 bn (8% of The World’s), $2,454 per capita (36% of China’s)

Derived from Angus Maddison’s world model found here: Historical Statistics of the World Economy: 1-2008 AD – knoema.com

So assuming the British hadn’t replaced the Mughals, and India could have maintained it’s 27% share or the World population, in 1946 it should have had a population of 700 million, not 415. So that’s 285 million people and $157 bn/year, for starters, then multiply the number by the number of lost generations / years, and you obtain some big numbers.

Similarly if India had maintained its GDP share, with it could have achieved with it’s native technologies, with a population of between 2 and 2.2bn, in 1947 (land and diseases permitting), you’re looking at 1.6 to 1.8bn bodies that need to be accounted for and $990 bn/year, multiplying back the numbers get very big.

Going further and if the Mughal and Maratha empires had decided to build 100’s of IIT in mid 1700’s, rather than fight each other, and suck up to the Britishers, the numbers get very, very, very big.

Or looking at it numerically:

• 415 million > 165 million citizens
• $258.164 bn > $90.75 bn/year GDP
• $622 > $550 per capita.