King Charles is set to receive £132 million in annual income next year from the sovereign grant, unchanged from last year, despite a surge in profits from the Crown Estate.
The estate, which owns the seabed around much of the United Kingdom, earned £1.1 billion in the past financial year, more than doubling its profits over two years due to booming offshore wind developments.
Developers pay large sums to secure seabed leases, boosting estate revenues.
The monarchy receives a portion of these profits to fund official duties and the ongoing £369 million refurbishment of Buckingham Palace.
The grant rate was reduced last year from 25% to 12% to temper the windfall.
The estate, valued at £15 billion, also holds central London properties and rural land. It is redeveloping a large area in the West End and expanding housing projects.
A £490 million redevelopment plan is underway, with ambitions to build up to 56,000 homes across the UK.