Wales' largest council said it will have to cut services and raise taxes because of a shortfall in its budget.
Cardiff council said "there will be services which we simply will be unable to offer to residents in the future".
Cabinet member for finance Chris Weaver said the council was working on the assumption it will increase council tax by 4.3% in 2019-20.
He said the authority is facing a £91m black hole in its budget over the next three years.
In an interview with BBC Wales, Mr Weaver said it was too early to name specific services which would be cut, but that a consultation with taxpayers would be launched in the autumn.
In a budget strategy released today the council said it has identified £66m in savings over the next three years from an annual budget of £609m, but is still faced with finding another £25m.
As well as adjusting council tax, it is looking at capping increases on schools budgets or using its reserves.
Mr Weaver said the Labour-run authority expected to increase council tax and had "made an assumption of a 4.3% rise next year".
"However that is subject to so much change because we do not have the final settlement yet," he said.
He added: "A four or five per cent increase in council tax would only bring in around £6m which comes nowhere near to bridging the gap."
Mr Weaver also told BBC Wales that the council had £93m in reserves and would be using £1.5m of that money next year, but warned that using reserves was "part of the equation, but not the solution".
Council budgets are made up of the grant from the Welsh Government, council tax, and charges for services such as parking.
In last year's provisional settlement from the Welsh Government, Cardiff council was the only local authority to receive an increase in its budget, rising by 0.2%.
At the time, Finance Secretary Mark Drakeford said "Local authorities will need to look at their reserves as well to see if they can squeeze some money out."
A Welsh Government spokesman said: "We are all working against a backdrop of austerity thanks to years of successive cuts in funding from the UK government.
"The cabinet secretary told local authorities to prepare for the tougher times and harder choices that lay ahead, and that they should take account of all the resources available to them."