<prompt> Human: So my sister and I were both single and decided to buy a house together. She had a good amount in savings but didnt have the income for a mortgage whereas I had a the income but no savings. The idea was that if one of us got married the house could go one way or the other. Well, that ended up being me, so we decided she was moving out. However, now that thats done, Im not sure exactly whats fair to pay back. I kept good track of the funds, but now Im hung up on what would be fair and right. She isnt a numbers person and trusts me to make the right call.Heres the details. Id appreciate some advice and some math.The house cost 155,000 when we bought it, but was worth 135,000 when she moved out. Initially, she paid a down payment of 8,000. During the years we lived together, I paid 60,000 and she paid 40,000 paid at roughly the same rate, over time. When she moved out, we still owed 115,000.With all this in mind, what do I owe her, and how did you come about that number? If there are other details that are needed, let me know, and I can try to offer them up.UPDATE: All paid off. Thanks for the advice all, especially, uB_P_G. I cut her a check, handed it over, and shes happy with the amount. I sided in her favor a bit, cause why not. Now we are debt free, except for the house, so everyones happy. Assistant: Does your sister agree the house was worth 135,000? If she does then utraken has the correct answer. If she does then you will need to come to an agreement about the value of the house and then use the same formula utraken did above.Human: Thats one of the things that makes it a little messier. At the time of refinance, when she moved out, it was appraised at 135k. I havent paid her back yet, and since then, it has gone up in value a bit, but hasnt been appraised. But I think I should use the refinance amount and not a current estimate of value.  <response>: I would say she owns 44.4 of the equity until you buy her out. Think about it in reverse. If the house had gone down since she moved out would you still want to pay her 8.8k. 