How long do I have to live with stage IV untreated cervical cancer?

It depends on the si. The site of metastases determines the prognosis and survival. Most patients will live from one to two years depending on where the cancer has spread to. Once the vital organs like liver or lungs are involved then it is likely to be about one year or less. You should actually consider taking treatment with chemotherapy which is quite well tolerated and can extend life for another one or two years.