Royal accounts could suffer a potential £35m shortfall due to coronavirus.
The impact of lockdown on visitor numbers to venues such as Buckingham Palace and Windsor Castle will lead to an estimated £15m loss of income over the next three years, the Keeper of the Privy Purse said.
And a 10-year £369m budget to refurbish Buckingham Palace is expected to be £20m short, Sir Michael Stevens added.
He said the royal household had "no intention" of asking for extra funding.
Sir Michael said the royal household would try to manage the "financial challenges" of the pandemic "through our own efforts and efficiencies".
A pay freeze for royal staff was implemented in April and there is also a halt on recruitment, with only business-critical posts being filled, though staff have not been furloughed.
The financial report covers the 12 months to 31 March - shortly after the UK government brought in restrictions on daily life, to curb the spread of coronavirus.
Other details revealed in the report include:
- The Duke and Duchess of Sussex's high-profile tour of southern Africa was the most costly official overseas trip in the past year, at nearly £246,000, including planning trips for royal staff
- Expenses for a two-day visit by the Prince of Wales to Oman to pay his condolences following the death of Sultan Qaboos bin Said included a charter flight which cost £210,345
- The Duke of York took a charter flight to Northern Ireland to attend the Royal Portrush Golf Club's Open championship, which cost £15,848
- Funding for the Cambridges and Sussexes contributed to a £5.6m bill for the Prince of Wales in 2019-2020, up 11% on the previous year.
The Queen's Sovereign Grant from the Treasury increased to £82.4m in 2019-20, up £200,000 on the previous year.
It includes £33m set aside for major work to update the electrical cabling, plumbing and heating at Buckingham Palace.
All major expenditure areas have increased, from payroll (up £1.2m to £24.4m), to travel (up £700,000 to £5.3m), and housekeeping and hospitality (up £300,000 to £2.6m).
According to a senior Palace source, Prince Harry and Meghan have made a "substantial contribution" to the Sovereign Grant for the rent and refurbishment of Frogmore Cottage, estimated at £2.4m in 2018-19. The payment will be disclosed in next year's report.
The Sovereign Grant is funded by profits from the Crown Estate - a multibillion-pound property portfolio that ranges from London's Regent Street to Ascot Racecourse.
The estate is managed by an independent organisation, with any profit paid to the Treasury for the benefit of all UK taxpayers.
Republic, a campaign group calling for the abolition of the monarchy, said the Sovereign Grant was "madness" and should be scrapped.
The group's chief executive, Graham Smith, said: "A 15% increase in travel costs when hospitals can't deliver the very best care to every person in need, when teachers are struggling to pay for the necessary books and equipment and the police are stretched to breaking point is scandalous."
Separate accounts published last week show the Crown Estate had a £345m profit for the Treasury for the last financial year but there were concerns about the future financial impact of Covid-19.
The Royal Collection Trust pays fees, in relation to running the opening of royal residences such as Buckingham Palace and Windsor Castle, to supplement the Sovereign Grant. But closures due to the lockdown are likely to cause its income to fall by tens of millions.