Seller Finance Calculator — Free Balloon, Yield & Subject-To

Seller finance is a note you can actually service. Subject-to is an existing payment you step into. Both live or die on monthly cash and the balloon you cannot see from the driveway.

On seller finance, the buyer puts down cash, signs a note, and amortizes over a long clock with a shorter balloon. Payment is standard P&I on the note. Remaining balance at the balloon year is the check someone has to write — refinance, sell, or extend. Interest to balloon is everything paid minus principal reduction. That is the seller's coupon in dollars. Equity at balloon is sale price minus remaining balance, a rough picture of what is left to recast.

Monthly cash on this screen is market rent minus the note payment — a buyer-operator view. Yield on down is that annual cash over the down payment. If you are the seller, read payment and interest to balloon as your income engine, and balloon as your exit risk. If you are the buyer, read payment versus rent and whether the balloon is a cliff you can actually refinance in this rate world.

Subject-to flips the structure. There is already a loan. You type balance, the real payment (or leave it to modeled P&I), rate, remaining term, the price you are paying the seller, and market rent. Equity spread is price minus remaining balance — what you are paying for the privilege of stepping into that note. Monthly cash is rent minus the payment you just inherited. Cheap spread with negative cash is still a problem. Fat cash with a two-year remaining term is a different problem.

None of this is a license to hide a loan from a servicer or to ignore due-on-sale. That is legal work. This is arithmetic so you know whether the payment even works if the paperwork does.

Balloons sneak up. A 30-year amortization with a 5-year balloon feels like a 30-year loan in month one. In month 58 it is a refinance in whatever rate market exists then. Model the remaining balance and ask if that number is financeable without a miracle.

Lease option is the cousin when you want control without a note yet. Wholesale is the cousin when you will not hold the paper. Run the one that matches the contract you will actually sign.

The identities

Payment = standard P&I
Balloon = remaining balance after balloon years

Subject-to cash flow is rent minus the existing or modeled payment. Equity spread is price − balance.

How people blow the result

• Ignoring the balloon because amortization is 30 years.
• Using interest-only in your head while typing an amortizing note.
• On subject-to, typing asking price as if the loan balance were equity you own.

FAQ