Anti-monarchy campaigners have claimed the “true cost” of the royal family to the public is more than £500 million a year.
Republic, an organisation which campaigns for an elected head of state, has published a report analysing existing data, studies and newspaper reports about royal finances and concluded the monarchy costs £510 million annually.
Official royal accounts released earlier this year revealed the monarchy is to receive a boost of more than £45 million, with a 53% jump in its annual income to more than £130 million.
Officials have said the increase will be used to help fund the final stages of the 10-year, £369 million reservicing programme, updating Buckingham Palace’s electrical cabling, plumbing and heating system.
Graham Smith, chief executive of Republic, said: “If (Chancellor) Rachel Reeves thinks tough decisions are needed in these difficult times, she needs to start with the royals.
“We’re being told the Budget will be painful.
“Well if that’s true, the cuts must start at the top.
“How can we talk about cutting the winter fuel allowance while wasting half a billion pounds on the royals?
“How does the Government defend this rhetoric of painful decisions when the royals cost us enough to pay 18,000 NHS nurses?
“Yet the true cost of the monarchy is well over half a billion pounds.”
Republic claims the biggest cost was an estimated £150 million for royal security and a further estimated £96 million in “lost revenue”, the report argues, as royal residences “occupied by the royal family cannot be used to their full potential by the state”.