Seller Financing Calculator

Background.

Use Seller Financing Calculator when you need to amortize a seller-carried principal and identify any balloon balance at the agreed term. Seller financing replaces a conventional lender for part or all of the price, but the note still follows its negotiated rate and amortization. Here the arithmetic follows “payment = principal × monthly rate ÷ (1 − (1 + monthly rate)^−months),” rather than silently mixing alternatives.

The editable entries are financed principal, annual interest rate, amortization term, upfront financing cost. Use values from the document or measurement that governs this seller financing question; the defaults are only the worked fixture below. The most consequential input mistake would be to ignore that a payment term shorter than amortization creates a balloon; liens, servicing, ability-to-repay law and default remedies are not computed.

Fannie Mae Selling Guide B3-3.1-08, Rental Income; documented gross and net rental-income treatment documents the convention or governing rule used here. The seller financing output is a transparent scenario under those facts: it does not manufacture an unentered market price, professional determination, carrier quote, legal eligibility finding or locally adopted code value.

What is seller financing calculator?

Seller Financing is the relationship behind this decision: seller financing replaces a conventional lender for part or all of the price, but the note still follows its negotiated rate and amortization. On this page it means payment = principal × monthly rate ÷ (1 − (1 + monthly rate)^−months). A payment term shorter than amortization creates a balloon; liens, servicing, ability-to-repay law and default remedies are not computed; that is the line between the reported quantity and a broader real estate analysis.

How to use this calculator.

1. 01Confirm that “payment = principal × monthly rate ÷ (1 − (1 + monthly rate)^−months)” matches the seller financing convention you need.
2. 02Replace the fixture values for financed principal, annual interest rate, amortization term, upfront financing cost with dated values from the governing record.
3. 03Keep all currencies, measurement units and time periods on the same basis before calculating.
4. 04Read monthly principal and interest together with this boundary: A payment term shorter than amortization creates a balloon; liens, servicing, ability-to-repay law and default remedies are not computed.

The formula.

The calculation uses payment = principal × monthly rate ÷ (1 − (1 + monthly rate)^−months). In this seller financing model, the entered terms are financed principal, annual interest rate, amortization term, upfront financing cost. Seller financing replaces a conventional lender for part or all of the price, but the note still follows its negotiated rate and amortization, which is why the relationship is presented under this name rather than as a universal alternative. A payment term shorter than amortization creates a balloon; liens, servicing, ability-to-repay law and default remedies are not computed. Calculations keep full decimal precision through the relationship and round only the returned display values.

A worked example.

Frequently asked questions.

References& sources.

1. [1]Fannie Mae Selling Guide B3-3.1-08, Rental Income; documented gross and net rental-income treatment. Retrieved 2026-08-07. access: open unless marked otherwise.
2. [2]Freddie Mac, Modeling Multifamily Potential Rental Income; current rent roll, concessions and vacancy treatment. Retrieved 2026-08-07. access: open unless marked otherwise.
3. [3]U.S. Consumer Financial Protection Bureau. Regulation Z (12 CFR Part 1026), Truth in Lending. Retrieved 2026-08-07. independence: primary; access: open.