What's Windsor Castle Worth? The Oldest Inhabited Castle in the World
Image: Diliff, via Wikimedia Commons (CC-BY 2.5)
William the Conqueror started building Windsor Castle in 1070. It has been continuously occupied by the British monarch ever since — 956 years and counting. It is the oldest and largest continuously inhabited castle in the world, and the working weekend home of the British monarch.
A defensive perimeter around London
Windsor Castle was one of nine fortresses William the Conqueror built around the perimeter of London after the Conquest. The site, on a chalk bluff above the Thames, was chosen for its commanding view of the river approach to the city and its proximity to the royal forest of Windsor — a hunting ground William inherited from the Saxon kings. The earliest works were a wooden motte-and-bailey castle, replaced from around 1170 onwards by stone fortifications under Henry II.
The castle that visitors see today is the product of nine centuries of continuous building. The Round Tower, perched on top of the original Norman motte, was rebuilt in stone in the 12th century and substantially extended in 1833 by Sir Jeffry Wyatville. The State Apartments, on the north side of the Upper Ward, were rebuilt repeatedly through the 14th, 17th, 18th, and 19th centuries — most spectacularly by Charles II, who employed Hugh May to create a baroque palace in the 1670s, and then by George IV, who employed Wyatville to remodel the entire castle in the Gothic Revival style in the 1820s.
St George's Chapel — the spiritual home of the Order of the Garter, the senior order of British chivalry — is one of the great late Perpendicular Gothic churches of England. Begun by Edward IV in 1475 and completed under Henry VII in 1528, it contains the tombs of ten English monarchs including Henry VIII, Charles I, Edward IV, George VI, and Elizabeth II. The vaulted ceiling and the wooden choir stalls beneath the carved hatchments of the Garter Knights are among the finest medieval interiors in Britain.
The fire and the recovery
On 20 November 1992, a fire broke out in the Queen's Private Chapel and spread through several of the State Apartments, including St George's Hall, the Crimson Drawing Room, and the Octagon Dining Room. Around 9,000 square metres of the castle were damaged. The recovery took five years and cost £37 million.
The fire prompted a structural change in how the Royal Family funded the cost of the upkeep of the castle. Buckingham Palace was opened to paying visitors during August and September from 1993 onwards (it had previously been closed entirely to the public), and the resulting income contributed to the Windsor restoration. The State Apartments at Windsor were reopened in 1997 to coincide with the 50th wedding anniversary of Queen Elizabeth II and Prince Philip.
A working weekend home
Windsor Castle is the largest occupied castle in the world. The State Apartments are used regularly for state ceremonial functions — including the Garter Service, formal banquets for visiting heads of state, and investitures. The private apartments on the south-east side of the Upper Ward are the working weekend home of the monarch. Queen Elizabeth II spent most of her later years at Windsor, particularly during the COVID pandemic when she relocated full-time from Buckingham Palace.
The castle and its grounds extend to approximately 13 acres, surrounded by the 5,000-acre Windsor Great Park. The total floor area of the castle is approximately 45,000 square metres — making it one of the largest single buildings, by floor area, in any private residential use in the world.
Valuing the unsellable
Like Buckingham Palace and the Tower of London, Windsor Castle is held by the Crown in trust for the sovereign of the day. It cannot be sold, mortgaged, or used as security. There is no Land Registry transaction record for the castle, and there will not be one. Any valuation is, accordingly, an academic exercise.
A defensible academic range, accounting for the 13-acre castle site, the Grade I listed buildings, the unique heritage and ceremonial status, and the genuine impossibility of any actual sale: £2 billion to £3.5 billion. The number is, by any conventional standard, deeply approximate; the asset is genuinely without comparable.
This is an indicative estimate, not a formal valuation. Windsor Castle is not, and will never be, on the market.
This valuation range was generated by open for offer’s proprietary valuation engine, combining comparable sales data from HM Land Registry, current market conditions, and independent multi-source analysis. For unique properties where direct comparables are extremely limited, the range reflects greater uncertainty — and we show that honestly. This is an indicative estimate, not a formal valuation. A RICS-accredited surveyor’s valuation would be required for any transaction.
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Frequently Asked Questions
Who owns Windsor Castle?
The Crown — held in trust for the sovereign. Like Buckingham Palace, it cannot be sold.
How old is Windsor Castle?
Construction began in 1070. It is the oldest continuously inhabited castle in the world.