Prince Charles is one of the top earners for the royal family, who according to Forbes are worth £20 billion (AUD$36.5 billion).
Of that amount $500 million (AUD$644 million) is owned by his mother Queen Elizabeth in personal assets, which will also pass down to the Prince of Wales when he becomes king.
According to the publication, Charles’ income comes primarily from his Duchy of Cornwall estate, which owns a significant amount of land and properties, and is said to be worth almost £1 billon (AUD$1.8 billion).
Despite its name, only 13 percent of the estate is actually in Cornwall however, with the rest spread out across 23 counties in England and Wales.
The Duchy of Cornwall website suggests the vast majority of its income used to support the public duties and charitable work of Charles, his wife Camilla, the Duchess of Cornwall, as well as his son Prince William and his wife the Duchess of Cambridge.
The same used to apply to his other son Prince Harry and his wife Meghan Markle, before they decided to step back as full-time members of the royal family and relocate to California.
The Duchy's website states: "Since 1337, the revenues from the Duchy have either passed to an eldest surviving son and heir or where there has not been one, the Sovereign. These revenues can be spent as the Heir or Sovereign see fit.
"However the current Prince of Wales chooses to use a substantial proportion of his income from the Duchy estate to meet the cost of his public and charitable work as well as the public and private lives of his family, The Duchess of Cornwall, The Duke and Duchess of Cambridge and The Duke and Duchess of Sussex, and their children."
Charles, 72, also receives funding from the Sovereign Grant, which meets the running expenses of the queen's official household as well as covering the maintenance of the Royal Palaces in England.
Hardest working member of the royal family
When it comes to working for the cash, Princess Anne was the hardest working member of the royal family in 2020, carrying out 148 official engagements, despite the coronavirus lockdown.
The Princess Royal spent 145 days carrying out public duties according to the Court Circular - the official record of past Royal engagements.
Behind her was her brother, Prince Charles, in second place, and her mother, the Queen in third.
In 2019 however, Anne was pipped at the post by Prince Charles, who completed more engagements than any other royal family member that year.
The 72-year-old attended a total of 521 functions in 2019 – a figure that takes into account engagements both in the UK and overseas, according to The Times.
It was also a busy travel year for Charles, who visited New Zealand, Germany, Cuba, Barbados, India and the Caribbean.
In total, the royal family undertook 3,567 engagements in 2019. Anne came second place after her elder brother, attending 506 engagements in 2019 – 15 fewer than Charles.
The pair’s younger brother, Prince Edward, completed 308 engagements, while The Queen undertook 295; Prince William 220; the Duchess of Cambridge 126; and the Duchess of Sussex 83.
Additional reporting by Bang Showbiz.