Fixed or Floating Rate — Which to Choose for a Swap
A fixed rate locks the amount you get for a set time; a floating rate settles when your deposit arrives. Matrimix shows both and asks you to confirm any change.
Choose a fixed rate when you need to know exactly how much you will receive, and a floating rate when the quote is better and you accept that the final amount can move a little. Matrimix, a non-custodial exchange aggregator that needs no registration, shows both rate types side by side with the full cost of each route, so you compare final amounts rather than promises.
What the two rate types mean
Fixed rate. The provider locks the amount you receive for a set time window. If your deposit arrives within that window and matches the order, you get exactly the quoted amount. The order page tells you how many minutes the amount is locked.
Floating rate. The quote is an estimate. The final amount is calculated at the market rate when your deposit arrives and is processed. It can end up slightly higher or lower than the estimate. Matrimix marks such amounts with "≈".
Which rate types are available depends on the provider and the pair. Some routes offer only one.
Comparison table
| Fixed rate | Floating rate | |
|---|---|---|
| Amount you receive | Known in advance | Estimated, settled on arrival |
| Who carries market risk | The provider, during the lock window | You |
| Typical quote | Often includes a margin for that risk | Often closer to the market rate |
| Time limit | Send within the lock window | More tolerant of slow deposits |
| Best for | Paying an exact amount, volatile markets | Calm markets, flexible amounts |
| If the deposit is late | The rate may no longer apply | The swap uses the rate at arrival |
The "typical quote" row is a tendency, not a rule. Matrimix shows the full cost of every route before you confirm, so you can see which one is actually better for your amount right now.
When a fixed rate is better
- You need an exact amount — for example, to pay an invoice or top up an account with a set sum.
- The market is moving fast. A lock protects you from a drop between sending and processing.
- Your deposit will confirm quickly. You can send well within the lock window.
The trade-off: if your transaction is slow to confirm (for example, a low Bitcoin network fee) and misses the window, the provider may recalculate at the current rate or refund the deposit.
When a floating rate is better
- The floating quote is clearly higher than the fixed one for the same route.
- The market is calm, so the expected movement is small.
- You can't be sure how fast your deposit will confirm, and you prefer the swap to go through rather than hit a deadline.
The trade-off: the final amount can be lower than the estimate if the price moves against you.
What happens if the rate changes before you confirm
Quotes are live. Between the moment you see the route list and the moment you create the order, the provider may update its price. Matrimix checks this when you confirm. If the amount has changed, it shows you the new figure next to the old one and asks you to confirm again — the order is created only if the new amount suits you. Nothing is sent or locked until then.
After the order is created:
- on a fixed route, the locked amount holds for the stated time;
- on a floating route, the final amount follows the market until your deposit is processed.
Refunds in both cases
Every Matrimix order asks for a refund address. If a swap can't complete — the deposit arrives too late, is below the minimum, or the provider can't process it — it is refunded to that address. If the executing exchange holds a deposit for a compliance (AML) review, it refunds only to the address you paid from and that can take several days, so pay from a wallet you control.
Every destination and refund address is also screened against the OFAC SDN sanctions list, updated every 12 hours.
Practical tips
- Compare the final amount, not the rate, in the route list.
- For a fixed rate, send the deposit right after confirming and use a normal network fee.
- Send exactly the amount in the order, on the network shown.
- Check provider availability on /status before large swaps.
- See how fees are built on /fees, and try a pair such as BTC to XMR on the exchange.
FAQ
Is a fixed rate always more expensive?
Not always. Fixed quotes often include a margin for market risk, but providers compete, and sometimes the fixed route gives the better final amount. Matrimix shows both before you confirm.
What if I send my deposit after the fixed-rate window ends?
The provider may recalculate the swap at the current rate or refund the deposit to your refund address. Check the order page for the current status.
Will Matrimix change my amount without asking?
No. If the quote changes before the order is created, Matrimix shows the new amount and asks you to confirm it. On a floating route the final amount depends on the rate when your deposit arrives, which is stated in the quote.