Sneijder: Real treated me very badly
Both clubs have yet to confirm the deal but Spanish and Italian media reported on Thursday the fee was 15 million euros plus another three million euros linked to objectives.
"What happened with me is very strange," said Sneijder. "They (Real) treated me very badly but to tell the truth I would prefer not to talk about it."
He told the Spanish sports daily Marca: "I am going to a great club, of that I have no doubt".
The Dutch international has agreed a five-year contract with a net annual salary of four million euros, media reported. Sneijder told his website he was on his way to Italy for a medical.
Coach Jose Mourinho said he may play for Inter in Saturday's derby against AC Milan if he completed his move in time to train on Friday.
"If he manages to do all the tests and train tomorrow he could become an option," Mourinho was quoted as saying by Italian media.