<prompt> Human: EDIT A little more background. I share this house with my GF soon to be wife who has her own retirement account and investments. The house PI makes up 14 of our pretax income so we still have about 1,600 monthly after all our expenses. We plan to live at this house for the rest of our lives and we are putting money into the house in renovations. We are at 65 LTV.x200B;A couple years ago when interest rates bottomed out I made the choice of refinancing my 30 year into a 15 year at a 2.75 rate. I was borrowing at a rate of 4.375 prior to this. But I had the option of 3.5 if I wanted to refinance back into a 30 year. The balance on my existing mortgage was 190,000. The monthly difference worked out to around 436x200B;My decision to do this was based on fear over my parents mistakes with mortgages. This made it so I would be free of a mortgage by age 44. Sounded great and for some the freedom is worth the hit towards retirementx200B;I am posting this because maybe my math is flawed. Or maybe my math is right and this could help someone.x200B;I currently put 667 monthly into 401k. This doesnt change in either scenario. The below scenario is based on 7 returns compounded yearlyx200B;30 year853.18 monthly and 117,146.57 interestx200B;15 year1289.38 monthly and 42,088.60 in interestx200B;30 year scenario:436.20 extra towards 401kx200B;666.67 monthly to 401k 436.20 1102.87 monthly for 30 yearsx200B;1,250,135.61 by age 59x200B;15 year scenario:666.67 monthly to 401k 201,132.69 after 15 yearsx200B;then 666.67 1,289.38 1956.05 monthly for the next 15 yearsx200B;1,144,774.92 in savings by age 59x200B;So it looks like i shot myself in the foot 100,000x200B;  <response>: There is one thing no one has mentioned here - you are implicitly assuming your path is linear, and that you will not want to do something quite different in the future. By paying off your house in 15 years, you may have cost yourself some retirement savings, but you also may have set yourself up to have much more flexibility at age 44. You will have a huge asset completely paid off, meaning you can take on other debt more readily, either in the form of a HELOC or a small business loan or something else. Even if you dont take on more debt, you could change jobs or choose not to work for a period if you want to spend your time in other ways. In some ways, this could end up being worth much more to you than 100k, but you may not know that until youre 44 ; 