Free reverse calculator
Reverse Seller Financing Calculator
Seller says, “I need $2,000 a month,” or you know principal and interest have to stay under a number. The same job shows up as owner financing. Enter the payment first and work backward to the price and seller-financed balance those terms can support.
Reverse seller financing calculator
Start with the payment. Solve the price.
Enter the monthly payment the seller wants. The calculator works backward to the seller-financed principal and total purchase price those terms support.
Seller-financed principal + cash down.
Supported by $2,000/month at 5% over 30 years.
Estimated remaining principal after 60 payments.
This solves note math only. It does not establish property value or account for taxes, insurance, servicing, legal fees, closing costs, or deal-specific requirements.
Why reverse the math?
Seller financing conversations often start with a payment cap, not a purchase price.
A seller may know exactly what they want to receive each month without knowing what interest rate, amortization period, or financed principal produces that payment. A buyer may have the same problem from the other side: “We need to keep P&I under $2,000 a month.” That is where a normal loan calculator is backwards for the conversation.
A reverse seller financing calculator starts with the monthly payment and solves for the principal that payment can support. Add the buyer’s cash down and you have the purchase price that is mathematically consistent with those terms.
That payment supports about $372,563 of seller-financed principal. With $50,000 down, the corresponding purchase price is about $422,563.
See the full $2,000/month example →The formula behind the reverse calculator
For a standard fixed-rate amortizing seller note, the financed principal is the present value of the monthly payment stream:
Principal = Payment × (1 − (1+r)^−n) ÷ r
Payment is the monthly principal-and-interest payment, r is the monthly interest rate, and n is the number of monthly payments in the amortization period.
Once the financed principal is known:
Purchase Price = Seller-Financed Principal + Cash Down
Why the interest rate changes the price so much
When the seller’s desired payment stays fixed, the rate becomes a purchase-price lever. A lower rate lets more of the same monthly payment support principal instead of interest. A higher rate does the opposite.
That means two offers can give the seller the exact same monthly income while supporting materially different purchase prices. The rate-sensitivity table in the calculator makes that tradeoff visible immediately.
Amortization and balloon are different variables
The amortization period determines how the regular monthly payment relates to principal. The balloon determines when the remaining unpaid balance must be paid off.
For example, a 30-year amortization with a 5-year balloon uses a payment sized on a 30-year schedule, but the remaining balance becomes due after 60 payments. The shorter balloon does not automatically make the scheduled monthly payment larger.
See the complete 30-year amortization with a 5-year balloon example for the payoff math.
Use reverse math as a negotiation constraint—not a valuation
If a seller says, “I need $2,500 per month,” reverse math gives you a clean way to structure the conversation:
“If $2,500 per month is the number we need to protect, the price depends on the interest rate, amortization, and cash down. We can solve the structure around that payment.”
That result is not an appraisal and it does not tell either side what they should accept. It tells you which combinations of terms are internally consistent.
Then test whether the property can carry the payment.
A structure can be mathematically valid for the seller and still be a bad fit for the property. After solving the seller’s payment target, open the full Seller Finance Lab workspace to compare the note against rent, operating expenses, cash flow, DSCR, alternate scenarios, and the constraint solver.
Take the reverse-solved structure into negotiation mode.
Compare scenarios, see what the terms are worth, find viable combinations, share the deal, and generate the PDF.
FAQ
Reverse seller financing questions
What is a reverse seller financing calculator?+
A reverse seller financing calculator starts with the monthly payment the seller wants and works backward to the seller-financed principal and purchase price supported by that payment, interest rate, amortization period, and cash down.
How do I calculate purchase price from a seller’s desired monthly payment?+
First calculate the present value of the target monthly payment over the amortization period at the negotiated interest rate. That present value is the seller-financed principal. Add the buyer’s cash down to get the corresponding purchase price.
Does a balloon payment change the purchase price supported by the monthly payment?+
The amortization period and interest rate determine the normal payment-to-principal relationship. A balloon changes when the remaining unpaid principal becomes due. It does not by itself change the standard amortized monthly payment.
Why does a lower interest rate support a higher purchase price?+
When the monthly payment is held constant, less of each payment is required for interest at a lower rate. That allows the same payment to support a larger principal balance, which can translate into a higher purchase price if cash down stays the same.
Is the calculated purchase price the property’s market value?+
No. The result only shows the purchase price mathematically supported by the financing constraints entered. Market value, property condition, income, taxes, legal requirements, and other deal factors must be evaluated separately.