Offer floor calculator
Offers arrive while you're doing something else and you have thirty seconds to decide. This gives you two numbers to hold in your head: the floor where you break even, and the floor where the sale is actually worth making.
Why the floor is higher than you think
The instinct is to compare an offer against what you paid. But the platform takes its cut of whatever the offer becomes, so an offer equal to your cost always loses money — you pay the fees out of your own pocket. This solves the problem in the correct direction: it searches for the price at which the after-fee payout covers your cost plus the profit you asked for.
The break-even line at the bottom is the number worth memorizing per platform. Anything below it is you paying someone to take your item. It's also the number that makes lowball offers easy to decline without agonizing — either the offer clears the floor or it doesn't.
One thing to add to your cost before you trust the floor: the postage, packaging, and mileage you actually spend on this sale. Sellers routinely forget those and then wonder why a technically profitable month left no money behind.
Questions
Should I just always hold out for full price?
Depends on your sell-through rate. If items sit for months, an offer above your floor converts dead inventory into money you can redeploy — often worth more than the extra you'd eventually squeeze out. If your stuff sells fast, hold.
What profit number should I put in?
Whatever makes the packing and shipping worth doing. Many resellers use a flat minimum per sale (say $10) precisely because the labor per order is roughly constant regardless of item value.
Does this account for the platform's discounted shipping?
Only through what you enter. If the buyer pays shipping, put it in the shipping field; if you eat it, add it to your cost. Both change the floor, which is exactly why free shipping offers feel worse than they look.