British Prime Minister David Cameron says a deal struck with EU leaders will give the UK "special status" and he will campaign with his "heart and soul" to stay in the union, reports the BBC.
The PM said the agreement, reached late on Friday after two days of talks in Brussels, would include a seven-year "emergency brake" on welfare payments.
He added the deal included changes to EU treaties and would be presented to his cabinet on Saturday at 10:00 GMT.
EU exit campaigners said the "hollow" deal offered only "very minor changes".
The agreement on renegotiating the UK's EU membership was announced by European Council president Donald Tusk, who tweeted: "Deal. Unanimous support for new settlement for #UKinEU."
It paves the way for the UK to hold an in/out referendum on EU membership, which has been promised by the end of 2017 but is expected in June this year.