King Charles is officially richer than his mother Queen Elizabeth was during her lifetime. Photo / Getty Images

King Charles reportedly has a personal net worth of £600 million, equivalent to around NZ$1.2 billion.

The Times has analysed the British monarch’s various income streams for its Sunday Times Rich List, with the King’s personal fortune eclipsing his late mother the Queen’s net wealth of £370 million (NZ$740 million).

A former aide told the publication Charles had managed to amass a significant net wealth over the years, after becoming meticulous with savings following his costly 1996 divorce from Diana, Princess of Wales – where he paid her an NZ$33 million lump sum and NZ$799,000 annual salary.

“He became prudent at tucking away some money from the Duchy [of Cornwall] after that wipe-out [of capital],” the source said.

The aforementioned duchy (a royal estate) is where a large portion of Charles’ earnings comes from.

There are two duchies in the UK – the Duchy of Lancaster and the Duchy of Cornwall – both property empires which primarily invest in land.

Traditionally, the heir to the throne inherits the Duchy of Cornwall, with William, Prince of Wales, now in charge of overseeing it after Charles became monarch last year.

Meanwhile, the Duchy of Lancaster sits in the hands of the reigning monarch, now Charles, who inherited it from his mother after her death in September.

The Duchy of Cornwall is estimated to be worth NZ$1.9 billion.

During his time overseeing the Duchy of Cornwall, Charles increased its annual profits by 42.6 per cent to NZ$50 million between 2011 and 2022.

Within that time period, Charles made NZ$425,364 million from the duchy. That income is not liable to tax payments, though Charles has voluntarily opted to pay income tax since 1993.

According to The Times, much of this revenue comes from “renting commercial properties” in other areas of the UK.

Meanwhile, the Duchy of Lancaster has NZ$1.3 billion of net assets.

Royals in charge of overseeing the respective duchies are not allowed to sell the assets – they technically don’t have outright ownership over the land – but they can pocket the annual revenue.

Royal finances, particularly the duchies, are a grey area. The palace is not required to be transparent about how the earnings from the duchies are spent, given they are “private” estates.

But there has often been debate over who should be entitled to the revenue – the palace or the British people.

Elsewhere, Sandringham and Balmoral are also two of Charles’ lucrative income streams.

The Times estimated a value of NZ$490 million for Sandringham, which also generates tourist money, and NZ$419 million total for Balmoral Castle and its estate.