FixedFloat Fixed Rate vs Float Rate Explained

On a single Tuesday in March 2026, the BTC/XMR pair moved 4.2% inside a six-minute window after a US regulatory leak about stablecoin oversight. Traders who had locked a fixed rate on FixedFloat ten minutes earlier walked away with exactly the Monero they were quoted — even though the spot market had reversed three times during their on-chain confirmation. Those who picked the float option that same morning saw their final XMR amount land 2.8% above the original estimate when the market snapped back. Same exchange, same pair, opposite outcomes — purely a function of which rate model they chose.

That tiny dropdown on FixedFloat — "Fixed" vs "Float" — is one of the most consequential choices in a no-account swap, and it is also one of the least understood. Most users default to whichever is selected, accept the quote, and never think about it again. But the gap between the two modes is where the platform makes its money, where users either save 1-3% or pay a hidden insurance premium, and where the entire UX of services like FixedFloat, ChangeNOW, SimpleSwap, and even Cake Wallet's in-app swap layer is built. This guide unpacks exactly what each option means, when each one is the right call, and how Monero users in particular should think about the trade-off before they paste an address and hit Exchange. We will also show where MoneroSwapper fits into the picture for users who want to route around the choice entirely.

What "Fixed" and "Float" Actually Mean Inside FixedFloat

The labels sound self-explanatory, but the mechanics are different in ways that matter. When FixedFloat displays a quote, it is not promising you spot market access — it is quoting the price at which it is willing to take the other side of your trade, plus or minus a service margin. The Fixed and Float modes determine who carries the risk for the price movement that happens between the moment you click Exchange and the moment your incoming transaction confirms on-chain.

• Fixed rate: FixedFloat guarantees the exact output amount shown at the moment of quoting. If BTC drops 5% during your three-confirmation wait, you still receive the XMR amount written on the order page. The platform absorbs the volatility — and prices that absorption into a wider spread, typically 0.4-1.2% above the float quote.
• Float rate: FixedFloat sends you whatever amount the market produces when your funds finally arrive and clear. Your incoming BTC is converted at the rate at confirmation time, not at order time. You get a tighter spread (often half that of fixed), but the final XMR figure is unknown until settlement.
• Spread, not slippage: Neither mode is "the real market price." Both already include FixedFloat's spread. The choice is about which moment the spread is calculated from, not whether a spread exists.
• Refund triggers differ: Fixed orders are refunded (minus a network fee) if the incoming amount falls outside a tight tolerance band — usually ±0.5%. Float orders simply convert whatever arrives, so partial transfers still execute.

FixedFloat's own documentation describes Fixed as a "guaranteed rate" and Float as a "market rate." That framing is technically accurate but misleading — the float rate is also not the live spot rate you would see on Kraken or Binance. It is FixedFloat's internal price feed at the moment of confirmation, which already includes their margin. Treat both labels as a description of timing, not as a description of where the price comes from.

How FixedFloat Actually Builds Each Quote

Behind the scenes, FixedFloat aggregates liquidity from several centralized venues and runs its own internal hedging book. When you request a Fixed quote for BTC to XMR, the engine performs three operations almost simultaneously: it reads the current mid-market price from its primary liquidity sources, applies the fixed-mode spread (which is wider precisely because it is committing to a price), and opens a hedge position on a backing venue to lock in the cost of the XMR it will eventually send you. The hedge is the reason the spread exists — FixedFloat is paying its own fees to neutralize the price risk so you can stop watching the chart.

The lifecycle of a fixed-rate order

A typical fixed-rate Monero swap on FixedFloat passes through four states: awaiting deposit, confirming, exchanging, and completed. The fixed quote is valid only during the awaiting-deposit window, which expires after a configurable period (commonly 10-30 minutes depending on the asset pair). If your Bitcoin transaction has not entered the mempool before that window closes, the order is voided and any later arrival is treated as an "unexpected deposit," which switches to manual reprocessing at a less favorable rate. This is the single most common failure mode for fixed orders, and it is why low-feerate transactions on a congested Bitcoin network often end up in dispute tickets.

The lifecycle of a float-rate order

Float orders are looser. There is still a quote timeout, but the displayed XMR amount is treated as an estimate from the start. When your funds arrive and clear the required confirmation depth (typically two confirmations for BTC into XMR), the engine takes a fresh price reading, applies the narrower float spread, and releases the corresponding XMR to your declared address. The user-visible result is that you might receive 0.4-1.5% more or less XMR than the original estimate, with the distribution skewing slightly negative on average — markets tend to chop, and the platform's spread always wins on the round trip.

If your incoming transaction is going to spend more than thirty minutes in the mempool, float rate is almost always the safer choice — fixed orders that miss the window become a support ticket, not a swap.

When to Pick Fixed, When to Pick Float

The honest answer is that neither mode is universally better — they optimize for different priorities. The decision should be driven by three variables: how time-sensitive your need is, how confident you are about confirmation timing, and how much volatility you expect during the transfer. The table below maps the most common scenarios to the rate type that minimizes regret.

Scenario	Recommended rate	Reasoning
Paying a fixed-amount Monero invoice (merchant, donation)	Fixed	You need an exact output. Pay the spread to guarantee the recipient gets the expected XMR.
Long-term accumulation of XMR with patience	Float	Saves 0.4-1.0% per swap on average. Over many swaps, the savings dominate.
Bitcoin mempool congested, low fee paid	Float	A fixed window may expire before confirmation, triggering refund or manual processing.
Major news event imminent (CPI print, ETF decision)	Fixed	Volatility skew is asymmetric; pay the premium to neutralize tail risk.
Swapping from a stable, slow-moving asset like USDT	Float	Spread saving outweighs near-zero source-side volatility.
First time using the platform, want predictability	Fixed	Reduces surprises, lets you learn the UX before optimizing.
Large notional (over 2 BTC equivalent)	Fixed, with split orders	Large floats absorb more market-impact slippage; splitting fixed orders bounds your worst case.

A nuance worth flagging: FixedFloat sometimes silently disables Fixed for specific pairs during low-liquidity periods or when its hedging venue is unavailable. If only Float is offered, it is not a UI glitch — it is a risk-management decision on their side, and forcing a fixed rate by routing through a different intermediate asset rarely helps once you account for the extra hop's spread.

Step-by-Step: Running the Same Swap Both Ways

The clearest way to internalize the difference is to walk through a single swap as it would unfold under each mode. Assume you are converting 0.1 BTC to XMR on a normal trading day with moderate volatility. The Bitcoin spot price is hypothetically 87,500 USD and the Monero spot price is 165 USD. The expected XMR before any spread is roughly 53.03.

1. Open FixedFloat and select the BTC to XMR pair. Enter 0.1 in the BTC field. Two output figures appear: a Fixed estimate of around 52.55 XMR and a Float estimate of around 52.80 XMR. The 0.25 XMR gap (roughly 0.47%) is the fixed-mode insurance premium.
2. Paste your Monero address. Use a fresh subaddress generated by your wallet — never reuse the primary address. If you are using a view-only setup, double-check the subaddress matches the index you expect to scan.
3. Choose your rate mode and click Exchange. The order page shows a deposit address, an exact BTC amount to send, and a countdown timer (longer for Float, shorter for Fixed). Copy the deposit address into your sending wallet.
4. Send the Bitcoin transaction with a competitive fee. Aim for inclusion in the next two blocks. For Fixed orders this is non-negotiable; for Float orders it merely shortens the unknown-rate window.
5. Wait for confirmations. FixedFloat requires two BTC confirmations for amounts under 0.5 BTC, three above that. During this wait, the Fixed order is locked at the original rate. The Float order is in limbo — the final amount has not been determined yet.
6. Settlement. Fixed mode releases the pre-quoted 52.55 XMR regardless of where the market moved. Float mode releases whatever the engine calculates at the moment of the second confirmation — could be 52.40, could be 53.20.
7. Receive in your Monero wallet. The transaction appears as an incoming output to your subaddress with the usual 10-block lock before it is spendable. Check the order page status; FixedFloat marks it as "completed" and shows the actual XMR sent.

If you run this experiment twice on the same day with small amounts, the takeaway is rarely the absolute price difference — it is the psychological one. Fixed orders feel boring and predictable, which is exactly what you want when sending a payment. Float orders feel slightly thrilling, which is exactly what you do not want when sending a payment.

Monero-Specific Considerations You Will Not Find in Generic Guides

Monero introduces wrinkles that do not apply to swaps between two transparent assets. Because XMR transactions use RingCT, Bulletproofs+, and stealth addresses, the receiving side has properties that interact with the rate-mode choice in non-obvious ways. Understanding these wrinkles is the difference between a clean swap and a confused support ticket.

First, Monero confirmations are slow relative to the price feed updates the exchange uses. A two-minute Monero block plus the ten-block spend lock means that even after FixedFloat marks your order "completed," you will not be able to forward those funds for roughly twenty minutes. For Fixed orders this is fine — you already know what arrived. For Float orders, this introduces a second layer of price uncertainty if you intended to immediately re-swap or spend.

Second, Monero's fungibility properties mean the source of your XMR is opaque downstream, but the source of your deposit BTC is not. If you are swapping from BTC and that BTC has a tainted history (mixer output, sanctioned exchange withdrawal), FixedFloat's AML systems may flag the deposit and freeze the order regardless of which rate mode you selected. The freeze is the same; the consequence differs. Fixed orders frozen mid-flight are refunded at the original rate. Float orders frozen mid-flight are refunded at whatever the engine decides constitutes a fair price at unfreeze time — usually worse than spot.

Third, FixedFloat does not allow editing the Monero destination address once an order is created. For Fixed orders this is fine because the amount is known. For Float orders, an address mistake combined with an unexpected rate movement can produce a recovery process that takes days. Always verify the address character-by-character before clicking Exchange, regardless of mode — but be especially careful with Float, where rate uncertainty compounds the urgency of any recovery.

Where MoneroSwapper Fits In

MoneroSwapper aggregates quotes from multiple no-account exchanges (including FixedFloat, ChangeNOW, SimpleSwap, StealthEx, and others) so that the fixed-vs-float decision is presented across providers rather than within a single one. For a given pair and amount, you might see a FixedFloat fixed quote of 52.55 XMR, a SimpleSwap fixed quote of 52.62 XMR, and a ChangeNOW float quote of 52.78 XMR — all sourced from the same underlying liquidity but routed through different spreads and hedging policies. Picking the highest fixed quote is often a better strategy than agonizing over fixed-vs-float within one platform.

The aggregator approach also surfaces an important data point: when several providers tighten their fixed-quote spreads in the same hour, it usually means the market makers behind them are confident about short-term volatility. When the fixed-vs-float gap widens across all aggregated venues, that confidence has eroded and a major price move is often pending. Treat MoneroSwapper's quote table as a low-rent volatility sentiment indicator alongside its primary job of finding you the best execution price.

FAQ

Is FixedFloat's fixed rate really fixed, even during a flash crash?

In the vast majority of cases, yes — provided your deposit arrives inside the quote window and clears the required confirmations. FixedFloat has historically honored fixed rates even through significant intraday moves, because it has already hedged the position on its backing venue. The exceptions are rare extreme-event scenarios where the hedge itself fails (a backing exchange halts withdrawals, for instance), in which case the platform typically processes the order at a renegotiated rate with an explanation rather than silently. Refund-and-retry at a new rate happens, but it is the documented escalation, not the default behavior.

Why is the float rate sometimes worse than the fixed rate?

The displayed float estimate is just that — an estimate at quote time. Markets can move against you between quote and confirmation. In aggregate, float beats fixed by 0.4-1.0% across many swaps, but the distribution has fat tails. About 15-20% of individual float swaps settle below the corresponding fixed quote. The expected value still favors float for patient long-term accumulators, but for a single time-sensitive swap, fixed remains the lower-regret option.

Can I switch from float to fixed after creating the order?

No. The rate mode is set at order creation and cannot be changed afterward. The hedging operation that backs a fixed quote happens at the moment of order creation, so switching mid-flight would require canceling and re-quoting. If you change your mind, the only path is to wait for the float order to complete or to wait for the quote window to expire, then start a new order with the desired mode. Some users hedge this by creating two small parallel orders — one fixed, one float — though this doubles the network fees.

Does FixedFloat report the rate I received to anyone?

FixedFloat operates without account creation and does not require KYC for most pair sizes, but it does retain order data on its own servers, including the deposit address, destination address, amount, and final rate. Whether this data is shared depends on jurisdiction and legal process. Since the Monero side of the swap is shielded by stealth addresses, RingCT, and the Dandelion++ broadcast layer, the destination XMR is not traceable from chain data — but the link between your deposit BTC and the FixedFloat order is visible to anyone who acquires the order record. Privacy-focused users typically run the source BTC through a CoinJoin round or use a non-KYC source before swapping.

What happens if I send the wrong amount on a fixed order?

If you underpay by more than the tolerance band (commonly 0.5%), the order is paused and you receive a notification with two options: accept the recalculated rate or refund the deposit minus network fees. If you overpay, FixedFloat typically processes the full amount at the original rate, but very large overpayments may also trigger a manual review. For float orders, any incoming amount is processed automatically — no underpayment penalty exists because there is no fixed expected amount to compare against. This is another quiet advantage of float for users who calculate their fees imprecisely.

Are aggregator quotes like MoneroSwapper's slower or less accurate than going direct?

Aggregator quotes are refreshed on a short interval and may lag the underlying provider's live quote by 5-15 seconds. For Fixed mode this is irrelevant — once you click through, the underlying provider re-confirms the rate. For Float mode it does not matter either, since the float rate is determined at confirmation regardless. The aggregator's value is comparison breadth, not real-time accuracy. The few seconds of staleness almost never affect the actual swap outcome.

Conclusion

The Fixed-vs-Float toggle on FixedFloat is not a UX afterthought — it is a deliberate offload of risk from the platform to the user, priced through the spread differential. Fixed mode is insurance with a known premium; Float mode is exposure with an unknown but on-average-better outcome. Match the mode to the use case: fixed for invoices, payments, and high-volatility windows; float for patient accumulation, low-volatility periods, and slow-confirming deposits. Apply the Monero-specific caveats around fungibility, address immutability, and the slow Monero block time, and the choice becomes mechanical rather than agonizing. For users who would rather compare across providers in one place — and surface the best fixed or float quote from FixedFloat alongside its competitors — MoneroSwapper handles the legwork without adding another spread layer on top.