- What it is
- A modest surplus of value held alongside the amount an order needs, set aside so a short arrival does not stall anything.
- How you get one
- Fund the wallet with a little more than the figure you were shown, and record in your plan that the extra is not spending money.
- Where to keep it
- In the same wallet as the payment, noted separately on paper so you can tell surplus from balance at a glance.
- How it goes wrong
- It gets spent without being noticed, or it was sized from a figure you read somewhere months ago and no longer holds.
- What fails without it
- A payment lands slightly under the required amount and the order sits unresolved while you arrange a top up.
- Time to acquire
- Minutes, once you have a wallet, though deciding how much feels right takes a bit of watching your own history.
What the surplus is actually absorbing
Two things eat into an amount on its way across. The first is whatever the network charges to move it, which is deducted from your side and varies by conditions on the day. The second is any conversion happening between the moment you looked at a figure and the moment the payment settled. Neither is unusual and neither is anybody misbehaving. They are simply the ordinary friction of value moving.
Headroom does not prevent that friction. It makes the friction irrelevant, which is a better outcome than trying to calculate it exactly. You are buying yourself the right to stop doing arithmetic under time pressure.
This page quotes no rates and no fees
Fees and rates move constantly, by hour and by network condition, and a figure written on a reference page begins aging the moment it is published. Any site that prints one is telling you about the day it was written rather than the day you are reading. So there is no number here, no percentage, and no rule of thumb dressed up as a percentage.
What you get instead is the shape of the thing. Look at the fee estimate your own wallet shows you at the moment of sending, because that estimate is live and this page is not. Then keep a margin comfortably above it rather than exactly on it.
Sizing it from your own history
The honest way to size a margin is to look at what happened last time. If you kept a rate note for previous payments you already have the raw material: what you intended to send, what actually arrived, and the gap between the two. A handful of those tells you more about your own situation than any general advice could.
People starting from zero tend to guess too low, because the visible fee is the one they account for and the conversion difference is the one they forget. Erring generous costs you nothing except a slightly larger surplus sitting in a wallet you control, which was going to have a resting balance anyway according to your plan.
Why this one goes stale
A margin sized six months ago was sized for six month old conditions. Network costs move. The amount you typically send moves. A surplus that was comfortable then can be thin now without anything visibly changing. That is why this item is marked as one that ages rather than one that keeps.
Refreshing it is not a chore. Glance at what your last two or three payments actually cost to move, adjust the figure in your notes, carry on. The trigger is usually a payment that arrived tighter than expected, which is a warning rather than a failure.
How you notice you have run out
The signal is a payment that lands under the required amount, leaving an order in a state that needs a second transfer to clear. That second transfer costs its own fee, takes its own time, and happens while you are watching a clock. It is recoverable and it is annoying, and the annoyance is entirely avoidable at the funding stage.
The quieter signal comes earlier: you find yourself checking the wallet balance against the order figure and the two are close enough that you have to think. That thinking is the tell. If you have to work out whether there is enough, there is not enough margin. Keep the order record to hand so a short payment can be described accurately if it comes to that.
Questions that come up
How much surplus is reasonable?
This page will not give you a figure and that refusal is deliberate. What is reasonable is set by network conditions on the day and by the size of your typical payment, neither of which a static page can know. The practical answer is to read the live estimate your own wallet shows at the moment of sending and keep enough above it that you do not have to think about the difference.
Does headroom just mean overpaying?
No. The surplus stays in your wallet rather than going anywhere. You are funding the wallet with more than the payment requires, not sending more than the payment requires. Whatever the payment does not consume remains yours and is governed by the third line of your balance plan, which is where you decide when it leaves.
What if I have no history to size it from?
Start generous and take notes. The first few payments are your sample, and a rate note for each one turns guesswork into a small dataset that belongs to you rather than to somebody writing general advice. After three or four you will have a sense of the range, and you can tighten the margin if it is clearly larger than it needs to be.