One pot, two things taken out of it
The fee is not billed separately and does not come from anywhere special. It comes out of the same holding the amount comes out of, at the same moment, in the same denomination. So the quantity that has to be covered is not the amount. It is the amount plus whatever the network is being paid to carry it, and both are drawn from one pot.
The failure that follows is specific, and it is not the one people expect. They expect a refusal. What usually happens instead is that the transfer goes out and the amount that arrives is short by the fee, because the wallet took what it needed rather than declining to proceed. Nothing disappeared. The shortfall simply landed on the other side of the transaction, on their accounting rather than yours, and you are left with an order underfunded by an awkward figure and a record showing that you paid.
That asymmetry is the point of the card. When there is nothing left for the fee, the party inconvenienced is the receiving side and the party who has to explain it is you. That is a harder position to argue from than a plain refusal, because what they see is a payment that does not match what was asked, which is indistinguishable from somebody who simply sent too little.
Fees also move. They respond to conditions on the network that have nothing to do with you, and can be materially different between one attempt and the next. No figure printed on a page like this one would still be true when read, which is why none appears. The margin is not a number to memorise. It is a habit of leaving room.
Settled value and matched value, both required
the balance has confirmed and can be spent supplies the pot. The fee comes out of spendable value, not out of the total, and this is where the two cards interlock most tightly. A holding that comfortably covers amount and fee on paper can be sitting on a spendable figure that covers only the amount, or neither. Worse, the margin can vanish while you do nothing, because change from an earlier send returns as a new arrival and has to age like any other. The margin you checked can be gone by the time you use it, and nothing announced its departure.
you hold the coin this order is priced in supplies the denomination the margin has to be in. A surplus held elsewhere is not a margin. The fee is paid in the denomination of the transfer and nothing outside that denomination participates, which is how somebody holding a considerable amount of value in total can still be unable to pay a fee.
Both parents have to hold at the same time for this card to be checkable. Value that is settled but wrongly denominated, or rightly denominated but not yet spendable, supports no margin at all.
What an underfunded transfer stops
One card sits below this one, and the stage narrows to it.
| Cannot hold | The reason it cannot |
|---|---|
| the total is covered at the moment you press the button | Covered means amount and fee together, out of spendable value, in the right denomination, at that instant. A margin that was adequate earlier is not evidence about the instant, because fees move and change can be unspendable. |
That card is about simultaneity, and this one supplies its most volatile input. The destination is stable once produced. The denomination does not change while you look at it. The fee is the input that can differ from one attempt to the next for reasons entirely outside the transaction, which means a margin verified in advance is not the same claim as a margin verified now. Checking the fee early and pressing later is precisely the mistake that card exists to name.
Downstream of it, escrow is still holding when the problem appears assumes an order that entered the mechanism properly funded. An order short by the fee tends to sit in a state that is neither paid nor unpaid, which is a poor place to argue from. It also spoils you can describe the problem in the market's own terms, because the difference you would be describing is one you introduced. A complaint that opens with an amount not matching what was requested has answered itself before it is read.
The block here is partial rather than total, which is unusual on this stage. An underfunded transfer does not stop everything the way a substituted destination does. It creates a shortfall that can sometimes be topped up, and topping up means another transfer, another fee and another wait.
Every remedy for a shortfall is itself a transfer, and carries its own fee and its own settlement wait. The cheapest moment to fix this is before the first send.
The order that never quite gets funded
Skipping this produces one of the tidiest looking failures on the map. You have at least the figure the order asks for. You type that figure into the amount field, exactly as given, because that is obviously the correct thing to do, and you send. The wallet confirms and shows the transfer going out.
On the other side, less arrives than was asked for. Sometimes the difference is small enough to be absorbed and you never learn about it. Sometimes it is not, and the order stays in a state meaning unpaid or partly paid. You look at your wallet, see a completed transfer, and reasonably conclude that you have paid. The confusion lands on the market side because that is where the visible discrepancy is, and the message you get will be about the amount, reading as though you sent the wrong figure, which from their position is what happened. The fee never enters that conversation, because from where they sit there is no fee, only an arrival that is short. This is also where people send a small second transfer to make up the difference and find that it too carries a fee.
Reading what leaves rather than what you typed
Set the amount. Then find where the wallet states the total that will actually leave your holding, which is usually shown separately and is usually not the number you typed. Compare that against what the order expects to arrive. A pass is that the arriving figure meets the requirement and the leaving figure sits inside your spendable value with room to spare. A fail is that the leaving figure equals what you typed, which means you have not found the right display yet, or that it consumes your spendable value exactly, which means the margin is zero and any movement in the fee turns this into a refusal or a shortfall.
A second habit is worth building: check whether the wallet is offering to deduct the fee from the amount rather than adding it on top. Both behaviours exist, they produce different arriving figures from identical inputs, and that difference is the thing this card is about.
Nothing here is an estimate
This page contains no fee figure and will not gain one, because a printed figure would be stale before it was useful and would be trusted anyway. The card is about the existence of headroom, not its size. questions deals with why this site prints no numbers of that kind, and the dependency map shows how narrow the remaining path is once this condition holds.