A used guitar is listed at $800. A buyer offers $720. You paid $450 for the guitar and $10 to set it up. Shipping is $75 charged / $65 you pay. Reverb marketplace is entered at 5% of the item, payment at 3.19% + $0.49. Declining the offer does not buy a sale at $800 — it buys a chance of one. Type your own odds and fallback on the calculator; this worked example uses a 30% chance of eventually reaching list, and $680 as the price you would realistically settle for otherwise.
| Path | Chance | Sale price | Net cash | vs taking it now |
|---|---|---|---|---|
| Take the offer now | 100% | $720.00 | $208.15 | +$0.00 |
| Wait, eventually reach list | 30% | $800.00 | $281.60 | +$73.45 |
| Wait, eventually settle for less | 70% | $680.00 | $171.43 | −$36.72 |
At a 30% chance of eventually reaching list — else settling near $680.00 — taking the $720.00 offer now still leaves $3.67 more in expectation than waiting. The break-even chance of eventually reaching list is 33.33%: below that, the certain $208.15 in hand beats the probability-weighted average of a better sale and a worse one; above it, waiting comes out ahead.
None of those sentences is advice to accept or refuse the offer, or a claim about your actual odds of reaching list — they are the arithmetic on the odds and prices you type. Nobody but the seller has a defensible number for "how often gear like this actually reaches list at this asking price," and this tool does not pretend to know it.
Every other comparison on this calculator treats "wait for list" as a sure thing. This is the one place it isn't. Offer versus a certain list sale is a different question, walked on should I take this Reverb offer. Whether a bump pays is on should I bump this Reverb listing. Your numbers stay in the browser. Comparing this guitar to eBay, Etsy, Amazon, or your own store? The where-to-sell calculator ranks Reverb against them with this item's price, shipping, and cost already filled in.
On the worked example — $720 offer, $800 list, $450 gear cost, 5% marketplace, 3.19%+$0.49 payment, a 30% typed chance of eventually reaching list and a $680 fallback price otherwise — taking the offer now leaves $208.15 for certain. Waiting leaves $204.48 in expectation (30% x $281.60 list, 70% x $171.43 fallback), which is $3.67 less. The break-even chance of eventually reaching list is 33.33%: below that, taking the offer wins on average; above it, waiting does.
The probability of eventually selling at list that makes the expected value of waiting exactly equal to taking the offer in hand. On the worked example it is 33.33%. If your honest odds of reaching this exact list price are lower than that, the offer in hand is worth more in expectation even though it feels like leaving money on the table.
Because an inbox that produced one lowball tends to produce more of them, and a "just wait for list" instinct usually assumes the next offer will be at least as good as the last one. It might not be. The calculator does not require the fallback to be lower than the offer in hand — type your own number — but defaulting it there keeps the illustration honest about the downside of holding out.
Reverb's own Making Offers guidance says an offer under roughly 65% of the asking price is auto-rejected by its Lowball Offer Policy before a seller ever sees it, and that most accepted offers land between about 70% and 95% of asking. The $720 offer against the $800 list on this page is 90% of asking — inside that typical band, not the kind of lowball Reverb already filters out. That says nothing about whether taking it beats waiting on this seller's own odds of a better offer; it only says the offer itself is not unusual.