Lord Chief Justice Sir Declan Morgan announced the decision in the Court of Appeal on Monday.
He identified no mitigating factors for a series of professional gun and bomb attacks designed to strike fear into the community at large.
He said: "Stone offered his services as a killer to any loyalist paramilitary group who would use him."
His decision on a prison tariff means the 58-year-old - who was freed for a six-year period under the terms of the Good Friday Agreement - may not be considered for release until 2018.
Stone, one of the most infamous figures to emerge during the Troubles, was jailed for life in 1989.
He had been convicted of six counts of murder, five attempted killings and three charges of conspiracy to murder.
His one-man vendetta included a gun and grenade strike on mourners at an IRA funeral in Milltown Cemetery, west Belfast in March 1988.
Stone killed three men attending the funeral, Thomas McErlean, John Murray and Kevin Brady, and wounded dozens more.
He was also the gunman in another three separate murders.
Milkman Patrick Brady was murdered in south Belfast November 1984, 12 months before joiner Kevin McPolin was shot in the head in Lisburn, Co Antrim.
In May 1987 Dermott Hackett, a bread server, was found dead in his van between Drumquin and Omagh.
He had been shot up to 16 times with a submachine gun.
There are serious aggravating factors. The effects on victims will live with them forever.
Sir Declan Morgan
Stone also confessed to a series of attempted murders and plots to kill, including a failed bid to assassinate Sinn Féin member Martin McGuinness during the late eighties.
He said he travelled to Derry by train before being picked up and taken to Mr McGuinness' home where he intended to shoot him through a bathroom window.
Stone later returned to the city and even went to the school his children attended but decided against carrying out an attack there, the court heard.
"He said that he then decided to attempt a 'head shot' at Mr McGuinness in a newsagents where he attended every morning," Sir Declan said.
Although the one-time loyalist icon was given an Armalite rifle, ammunition and the keys to a getaway car, his intended high-profile murder target failed to turn up.
He also told police that he had been asked to "do a hit" at the Enniskillen home of MP Owen Carron.
Years later Stone was released early as part of the Good Friday Agreement peace settlement.
But his fixation with the Sinn Féin leadership led to his being sent back to jail after turning up at Parliament Buildings, Stormont in November 2006 armed with explosives, knives, an axe and garrotte.
He was ultimately convicted of attempting to murder Mr McGuinness, along with party leader Gerry Adams, and given a 16-year sentence.
In 2011, Stone failed in a bid to get his conviction overturned, claiming the incident was "performance art".
However, Sir Declan's ruling dealt only with the life sentence tariff imposed for Stone's original killing spree.
It determines the minimum term he must serve before any release can even be considered, based on a risk assessment.
Stone made no representations and did not want an oral hearing before the ruling was delivered.
Backing the tariff imposed by the trial judge, Sir Declan said: "In this case the killings were professional.
"The killings were politically motivated in that they were directed at a section of the public identified by Stone as holding certain political views."
Stone armed himself with extensive weaponry, including a range of firearms, for his campaign of multiple murders, the judge pointed out.
He added: "The learned trial judge recommended a minimum term of 30 years before he should be considered for release and I agree. The appropriate minimum term in this case should be 30 years."
He will now serve the 18 years remaining on his 30 year sentence for the Milltown attack, after he completes his sentence for the assassination bid on the nationalist politicians.