What is Hereditary Revenue?
Hereditary Revenue is basically the income generated from Crown Estate. It mainly comprises of that income but isn't entirely limited to it.
What are the sources of the Royal Family's income?
There are two types of properties the Royal family has:
- Private Property or Privy purse
- Public property or Crown Estate
Currently, the income and expenditure of the family is governed as per Sovereign grant act of 2011. This law basically dictates how much money is to be paid to the monarch.
Total cost of running the monarchy is about 300 million pounds every year. For fiscal year 2016-2017, Her Majesty's Government paid her 42.8 million pound as per Sovereign grant act.
Queen herself owns Duchy of Lancaster in private capacity but she cannot sell it or anything as it is reserved in perpetuity for future royal generations. In financial year 2015, it provided 16 million pounds to the Royal Family. It is the main contributor to the Privy purse.
Duchy of Cornwall is reserved for the eldest Child of the Monarch (As pointed out by Daria, for clarification, eldest surviving son of the monarch and Heir to The Throne). It is currently held by Prince Charles. For year 2013, it provided 18.3 million pounds to the Prince.
Queen's consort Prince Phillip, Duke of Edinburgh receives 359,000 pounds per year from British Treasury. Previously Queen's cousins and all minor royals also received money from the Government but that practice was later abolished by Sovereign grant act 2011.
Crown also does not pay taxes.Crown bodies such as The Duchy of Lancaster are not subject to legislation concerning income tax, capital gains tax or inheritance tax. Furthermore, the Sovereign has no legal liability to pay such taxes. The Duchy of Cornwall has a Crown exemption and the Prince of Wales is not legally liable to pay income tax on Duchy revenues.
Queen also has her private income through her private investment portfolio. Her actual wealth is unknown however Jack Colville estimated her wealth at 2 million pounds in 1971 which would be 25 million today. Forbes magazine estimated her wealth to be 325 million pounds in 2011.
Other than that, Crown state alone produces hundreds of millions. In year 2011 it produced 211 million pounds.
Other assets like Royal Art collection and Royal palaces are held in trust and aren't personal property of the monarch.
Guardian puts the value of assets the Royals can actually use at 11-14 million pounds. You can find complete Excel sheet of Royal purse here which is compiled according to this Parliamentary report.