My boyfriend and I bought a property 3 years ago for $445,000.  He paid cash for his 50% share ($222,500) and I got a mortgage of $222,500 for my 50% share (which I alone have been paying for the past 3 years).  So far, I have paid off $61,370 (principal) which leaves $161,130 remaining on the mortgage. My boyfriend has been able to save this amount of money over the past 3 years and we have decided that it would be better for him to pay off the mortgage altogether rather than me pay the mortgage alone for the next 10 years.  This will mean that he has invested more than myself into the property and I would like to make sure that we document this so it is fair for both parties when selling it in the future. During our time as 50/50 owners over the past 3 years, the property has increased in price to $500K. Should this 50/50 profit of $55,000 be included/considered when doing the new % calculation? What is the best way to calculate the new % ownership? Would we need to use the current property price ($500K) rather than the purchase price?  Fyi - his contribution is $383,630 and mine is $61,370 (which totals the purchase price of $445K). Apologies if I am making it more complicated than it is.  Any advice/calculations much appreciated.