How this instrument works
Every real estate commission is quoted as a slice of the sale price — 5%, 6%, whatever the listing agreement sets. That figure is honest as far as it goes, but it answers a question few sellers are actually asking. The number that matters to a seller's pocket is not what the fee costs against the home's price tag; it's what the fee costs against the cash that lands in their account once the mortgage lender has been paid off from the same closing check. This instrument computes that second, truer ratio: commission as a percentage of net proceeds, after the loan balance is subtracted alongside the fee itself.
The two percentages can sit close together or drift far apart depending entirely on how much of the home is actually owned outright. A seller who bought years ago and paid the loan down owns most of the sale price as equity, so commission-against-net lands close to commission-against-price. A seller who bought recently, took cash out in a refinance, or is selling into a flat market with a large balance still owed keeps far less of the check, and the identical dollar commission then represents a much bigger bite out of what they actually walk away with — even though the rate written in the listing agreement never changed.
The arithmetic here only tracks three inputs: sale price, commission rate, and the remaining mortgage payoff. It has no view of property tax proration, transfer tax or stamp duty, title insurance, escrow or attorney fees, a second lien or HELOC beyond the single mortgage balance entered, or any capital gains tax the sale might trigger — every one of those can also reduce the seller's check, and a real closing statement will list them as separate lines. This sheet isolates one comparison — commission against price versus commission against net — and does not suggest a rate, a listing price, or whether selling now makes sense.
- Enter the agreed or expected sale price into Sale price, $.
- Set Commission rate, % to the percentage written into the listing agreement.
- Enter what is still owed to the mortgage lender into Remaining mortgage payoff, $.
- Read Commission, $ for the flat dollar fee, and Net proceeds to seller, $ for what is left after both the fee and the loan balance come out.
- Compare that against Commission as % of NET proceeds — the ratio that moves sharply as the mortgage payoff changes, even while the commission rate stays fixed.
Worked example — a $400,000 sale, $250,000 still owed
Take the default sheet: a $400,000 sale price, a 6% commission rate, and $250,000 still owed on the mortgage. Commission, $ reads $24,000.00 — plain arithmetic, 6% of the sale price, identical to what any flat-rate commission tool would return. Net proceeds to seller, $ reads $126,000.00, the $400,000 sale price minus that $24,000 fee minus the $250,000 payoff. Commission as % of NET proceeds then reads 19.0476190476 — roughly 19.05%, meaning the fee that looked like a modest 6% of the sale price is actually close to a fifth of the cash this seller keeps.
Move the mortgage payoff and the gap moves with it, even though nothing about the commission changed. Set the payoff to zero — a home owned free and clear — and net proceeds jumps to $376,000, dropping the ratio to about 6.38%, nearly matching the headline rate because there is no loan left to strip out of the check. Raise it instead to $350,000, leaving only $50,000 of paper equity, and the same $24,000 fee eats roughly 92.3% of the $26,000 that actually reaches the seller's account — three sellers, three payoff balances, one unchanged commission rate, and three entirely different true costs.
Questions
Why measure commission against net proceeds instead of the sale price?
Because the sale price is not the number that reaches the seller's bank account. The mortgage lender is paid off from the same closing check before anything else moves, so the cash a seller actually keeps is net proceeds, not price. A commission that is a modest share of price can be a much larger share of that smaller, real number — and net-proceeds is the figure this sheet is built to surface.
What exactly goes into Remaining mortgage payoff, $?
The outstanding balance owed to the mortgage lender as of closing, including any prepayment penalty the loan carries — the figure on a payoff statement, not the balance from an old monthly bill. Any second mortgage or home equity line against the property should be added into the same total, since this sheet only has one payoff field to subtract.
Can commission as a percentage of net proceeds go above 100%?
Yes, and it signals a seller whose closing costs would exceed their equity. If commission plus the mortgage payoff together approach or exceed the sale price, net proceeds shrinks toward zero or below, and the same fixed-rate commission then represents all or more of whatever cash is left — the sheet flags a non-positive net proceeds result rather than showing a misleading ratio.
Does a lower commission rate fix a thin-equity sale?
Only partly. Cutting the rate lowers the dollar commission and therefore raises net proceeds a little, but the mortgage payoff is unaffected by the rate at all — it is whatever is owed regardless of what the agent charges. A seller with little equity sees a bigger percentage improvement from paying the loan down further than from negotiating a percentage point off the commission.
Is net proceeds here the same as my profit or capital gain?
No. Net proceeds is cash in hand at closing — price minus commission minus the mortgage payoff — while profit or capital gain compares the sale price against what was originally paid for the home plus qualifying improvements, a separate calculation the tax code defines on its own terms and this sheet does not attempt.
Why do the other closing costs matter if they aren't in this formula?
Because they reduce the check the same way commission and the mortgage payoff do, just through separate line items — property tax prorations, transfer tax, title insurance, and escrow or attorney fees all vary by state and county. This sheet isolates the commission-versus-net comparison on purpose; a full closing disclosure will show every other line that also comes off the top.
References
- IRS Publication 523 — Selling Your Home
- Consumer Financial Protection Bureau — Owning a Home resources
Read this first: This instrument shows arithmetic, not advice. Real offers add fees, taxes and terms that vary by lender and place — verify the figures against your actual paperwork before deciding anything.