It's explained in excruciating detail here in the Sovereign Grant Framework Agreement[0], it is a grant of £85.9 million from Treasury. However, this amount is proportional to the value of Government revenue received from Crown Estates.
This is in keeping with the agreement between King George III and Parliament to give up revenue from the then unprofitable Crown Lands (now more precisely termed The Crown Estate[1]) in return for a Government stipend. The Crown Estate (which is still "owned by" The Crown[2]) now makes £345 million a year[3].
In contrast, The Duchy of Lancaster and The Duchy of Cornwall and the Royal Collection are not funded by Government, and are instead funded by the Royal Family, or admissions/donations, for the later.
Of course it costs the taxpayer. The government could simply stop handing over millions of pounds a year to these people if it wanted to. But it doesn't. This decision costs the taxpayer.
Taking the logic further - all privately owned property and revenue "costs the taxpayer", relative to the public owning it instead.
The UK treasury is formally Her Majesty's Treasury, and the sovereign grant paid to her is actually a small portion of the money she puts in through the Crown Estate. So she is a net donor to the treasury, although she gets a major out in that the Crown Estate is not subject to inheritance tax.
It's explained in excruciating detail here in the Sovereign Grant Framework Agreement[0], it is a grant of £85.9 million from Treasury. However, this amount is proportional to the value of Government revenue received from Crown Estates.
This is in keeping with the agreement between King George III and Parliament to give up revenue from the then unprofitable Crown Lands (now more precisely termed The Crown Estate[1]) in return for a Government stipend. The Crown Estate (which is still "owned by" The Crown[2]) now makes £345 million a year[3].
In contrast, The Duchy of Lancaster and The Duchy of Cornwall and the Royal Collection are not funded by Government, and are instead funded by the Royal Family, or admissions/donations, for the later.
[0] https://www.royal.uk/sites/default/files/media/sovereign_gra... [1] https://en.wikipedia.org/wiki/Crown_Estate [2] https://www.thecrownestate.co.uk/en-gb/resources/faqs/ [3] https://www.royal.uk/sites/default/files/media/sovereign_gra...