---
title: "Seller financing calculator for online business purchases"
url: https://firstpassmemo.com/tools/seller-financing-calculator/
updated: 2026-10-07
publisher: FirstPass Memo (hello@firstpassmemo.com)
---

Free calculator

# Seller financing calculator

The FirstPass Memo seller financing calculator is a free tool that shows the monthly note payment, the cash left for you and how long it takes to earn back your down payment when a seller carries part of the price, with an optional earnout. The business pays the note from its profit.

Runs in your browser. Nothing you type is sent to us or anyone else.

The calculator needs JavaScript, which runs only on this page. The formula is below if you prefer to work it out by hand.

## How it works

Note = price − down payment Monthly payment = note × r ÷ (1 − (1 + r)), where r = annual rate ÷ 12 Cash left = profit − payment − earnout share of profit

The calculator assumes profit stays flat and the note is repaid in equal monthly instalments. It counts the down payment as recovered when the cash left over, added up month by month, reaches it. Terms are whatever you and the seller agree; the calculator does not assume any.

A seller who agrees to carry a note keeps a stake in the business doing well after the sale, which is one reason buyers ask for it. The cost is that most of the early profit goes to the seller, so a fall in profit during the note comes out of your share first.

## Worked example

A composite deal, not a real one: a $90,000 purchase with $45,000 down and the other $45,000 as a 24-month note at 7%, on $3,000 of monthly profit.

The note payment is $2,014.77 a month, leaving you about $985 a month for two years. Total interest is about $3,354. You earn back the $45,000 down payment in about 31.1 months, against 30 months of payback on the full price if you had paid cash.

## Questions to send the seller

- Can you share 12 to 24 months of monthly revenue and profit, not only the recent average?

- How much handover support do you offer after the sale, for how long, and in what form?

- Why sell now, and what would you do with the business if it does not sell?

## Frequently asked questions

### What happens if profit falls during the note?

The payment stays the same, so the cash left for you falls first. If profit drops below the payment, you cover the gap from your own money. Enter a lower profit figure to see how much room the deal has.

### What is an earnout?

Part of the price paid later, usually as a share of profit or revenue for a set period, sometimes only if targets are met. Enter the share and the number of months to see its effect on your monthly cash. The calculator treats it as a share of the profit you enter.

### Who holds the business while the note is outstanding?

That depends on the agreement. Some sellers keep a security interest or control of key accounts until the note is paid. Have a lawyer review the terms before you sign.

## Related

- True payback calculator (https://firstpassmemo.com/tools/payback-calculator/)

- Red-flag checker (https://firstpassmemo.com/checker/)

- Is it worth it? Guides by business type (https://firstpassmemo.com/buy/)

- All calculators (https://firstpassmemo.com/tools/)

This calculator does arithmetic on the figures you enter. It is not investment, legal, tax or valuation advice, and it does not check whether a seller's figures are true.

---

FirstPass Memo is informational screening, not investment, legal, tax, accounting or valuation advice, and not an audit. Seller figures are not independently verified. HTML version: https://firstpassmemo.com/tools/seller-financing-calculator/