Price impactOften the largest cost on thin pairs; shown before signing
MEVBounded by your slippage tolerance; never itemised
Failed gasCharged in full for transactions that changed nothing
FBT Swap
What you should know
Ask what a swap costs and most people will name the platform fee. It is usually the easiest cost to see and frequently not the largest one.
The costs below are all real transfers of value away from you. None of them appears as a line labelled "fee", which is exactly why they are worth listing.
Price impact and spread
Trading into a pool that is shallow relative to your size costs you the difference between the market rate and your average fill. On a thin pair that is routinely several percent — an order of magnitude above any platform fee.
It is visible before you sign, as a price-impact figure. Most people read the output amount and not that number.
Extraction by transaction ordering
A sandwich takes value bounded by your slippage tolerance and leaves no trace on your receipt. You simply received slightly less than the quote implied, which is indistinguishable from ordinary market movement unless you inspect the block.
It is a cost, it is avoidable in part, and it is never invoiced.
Gas on transactions that did nothing
Failed swaps, approvals you never used, and transfers to the wrong place all consume gas. A pattern of reverts during volatility can quietly exceed what the successful trades cost in fees.
The fix is usually diagnostic rather than financial: find out why they revert instead of retrying with a bigger tolerance.
Standing permissions and stranded dust
An unused unlimited approval is not a monetary cost until it is, at which point it is the whole balance. Dust — token remainders too small to swap economically — is a smaller but permanent loss on every chain you have ever used.
FBT Swap charges 0.70% of the input on supported routes and shows it before you sign. The point of this page is that comparing interfaces on that number alone will mislead you.
At a glance
At a glance
01
Price impact
Often the largest cost on thin pairs; shown before signing
02
MEV
Bounded by your slippage tolerance; never itemised
03
Failed gas
Charged in full for transactions that changed nothing
04
Dust and approvals
Permanent small losses and open-ended risk respectively
FAQ
Frequently asked questions
Clear answers before you decide.
Which cost is usually biggest?+
For small trades, fixed network gas. For large trades on thin pairs, price impact. The platform fee is rarely the largest component in either case, which is why single-number comparisons are unreliable.
Can I measure what I actually paid?+
Yes. Compare the market mid-price at the block your transaction landed in against your effective rate, then subtract the known fees. The remainder is impact plus any extraction.
Does a zero-fee interface cost less overall?+
Not necessarily. An interface charging no explicit fee can route through worse paths, widen the quoted rate, or monetise order flow. The number that matters is tokens received, not the fee label.
Risk notice
Crypto assets are volatile and on-chain transactions cannot be reversed. You can lose money, including all of it. Nothing here is financial advice.
