Rates · 6 min read
Fixed vs floating rate crypto exchange: which one should you pick?
What a fixed rate really guarantees, what it costs right now compared with a floating one, and a simple rule for choosing between them.
By BTCSwap
Published
01What a floating rate is
With a floating rate, the number you see before sending is an estimate. The actual rate is taken when your deposit has confirmed on its blockchain and the desk executes the trade. If the market moved up in the meantime you receive more than the estimate; if it moved down, less.
Two things make floating the default on most swap services, including this one: it carries no deadline, so a slow deposit is never a problem; and because the desk takes no price risk while waiting for you, it can quote a tighter margin.
02What a fixed rate really guarantees
With a fixed rate, the amount you will receive is set when the order is created. Whatever the market does next, that amount is what gets paid out — provided your deposit arrives inside the window shown on the order page.
The guarantee has exactly two conditions, and they are the whole fine print:
- The deposit must arrive in time. The order page shows a countdown. A deposit that lands after it is not exchanged at the old price; on this desk it is returned to your refund address, minus the network fee to send it back.
- The amount must be the one on the order. The locked rate applies to the amount you quoted, not to whatever arrives.
Not every pair can be locked. A fixed rate exists only when both assets support it; when one does not, the module greys out the option and says why.
03What locking costs, right now
A desk that guarantees a price carries the risk of the market moving while it waits for your deposit. It prices that risk into the fixed quote, so a fixed rate is usually a little worse than the floating estimate at the same instant. Usually — not always.
- You send
- 0.1 BTC
- Floating, estimated
- 8,034.75 USDT
- Fixed, guaranteed
- 8,036.94 USDT
- Price of the lock
- none right now
Both quotes read from the desk at 17:43 UTC, BTC → USDT (TRC20). The gap widens when markets are volatile and narrows when they are calm.
Read that last figure as an insurance premium. Whether it is worth paying depends on what you are insuring against — which is the next section.
04How to choose, in one table
| Your situation | Pick | Why |
|---|---|---|
| You must receive an exact amount — an invoice, a payment | Fixed | The only way to know the payout before you send. |
| The market is moving fast and you deposit from your own wallet | Fixed | Your deposit is quick, so the deadline is easy; the lock protects you during confirmation. |
| You are withdrawing from an exchange to fund the swap | Floating | Exchange withdrawals are queued and batched; you do not control when the deposit lands. |
| You are sending BTC with a low fee, or the network is congested | Floating | A slow confirmation can outlast the fixed-rate window. |
| Stablecoin to stablecoin, or a calm market | Floating | There is little price risk to insure, so the premium buys nothing. |
| You simply want the best expected outcome | Floating | Over many swaps the tighter margin wins; any single one can go either way. |
05If your deposit misses the window
It happens — a withdrawal stuck in an exchange queue, a Bitcoin transaction waiting for a block. On this desk, the order page stops asking you to pay as soon as the window closes, so you do not send into an expired order by accident. It offers one button: start again with the same pair and amount, at the current price.
If the deposit was already on its way, it is not swapped at the old rate and not silently converted at a new one either: it goes back to the refund address on the order, minus the network fee. This is the practical reason to always fill in a refund address on a fixed-rate order.
06Questions people ask
Is the fixed rate always worse than the floating one?
Usually slightly, because it includes the cost of guaranteeing the price. But the two are quoted independently and the gap can close or even invert for a moment — which is why the module shows both numbers rather than a slogan.
How long is the rate locked for?
The desk sets the window when the order is created and the order page shows it as a countdown. Count on minutes, not hours: enough for a deposit from your own wallet, often not enough for a queued exchange withdrawal.
Can I switch from floating to fixed after creating the order?
No — the rate type is part of the order. If you have not sent anything yet, just create a new order with the other type; an unfunded order simply expires.
With a floating rate, can I end up with much less than estimated?
You get the market price at the moment your deposit confirms. Over the 10–60 minutes a typical swap takes, that is normally a small move in either direction; in a violent market it can be more. If that risk matters to you, that is what fixed is for.
Spotted something out of date? Tell us — the live figures refresh by themselves, the sentences around them are maintained by hand.
