King Charles built a huge fortune from his own property assets and from building housing developments that made him become a major landlord over the years.
The monarch's most valuable assets are Sandringham with its 20,000 acres and Balmoral, which is surrounded by 50,000 acres.
Sandringham has belonged to the royals for more than 160 years, it has 300 buildings and a grade II listed mansion.
Last year, property firm McCarthy Stone valued the principal residence at £55million - and the whole estate could be worth around £245million, according to agricultural land values supplied by estate agent Strutt & Parker.
Prince Albert acquired Balmoral for Queen Victoria in 1852 and the Scottish castle is valued at £60million.
It is surrounded by mountains, forests, lochs and grouse moors totalling 50,000 acres - with each acre worth between £600 and £1,800.
It is also surrounded by 150 other buildings including Birkhall, a house that Charles used for more than 20 years.
In total, the castle and wider estate are estimated to be worth around £120million.
Meanwhile, Charles has doubled revenues he achieves through rentals on property owned by the Duchies of Cornwall and Lancaster.
While Charles built a sustainable development in Dorset and began a similar project in Cornwall in the 1990s, the duchy was pushing up its income from renting commercial properties in London, Milton Keynes and Cornwall - almost doubling to £17.6million over the past decade.
The duchy is valued at more than £1 billion and is one of the largest and oldest estates in Britain. Dating back to the 14th century, holdings include the Oval cricket ground, 67,000 acres of Dartmoor and 260 farms.
Analysis by the Sunday Times shows that between 2012 and 2022, King Charles received £212.7 million from the duchy, opting to pay income tax on the figure.
The monarch's personal net is £600million - much higher than the late Queen, whose fortune was calculated at £370million last year.
One of his former aides said Charles carefully rebuilt his finances after his £17million divorce settlement from Diana in the 1990s.
The King's former adviser also said Charles was "tucking away some money" from the Duchy - and despite not giving an exact sum, it was described as "several tens of millions".
The monarch is known to be meticulous about switching off lights and during an interview with Vogue, he once said he hates throwing anything away - especially clothing items - if he knows he can reuse them in the future.
Charles also earned millions from his Duchy Originals range, with his branded biscuits, beer, herbal medicine and garden tools helping him earn a fortune.
The King set up the company based at his Highgrove House estate, Tetbury, in 1990. It has since become established as a leading organic and natural food brand, and in 2010 went into partnership with Waitrose.
