Cardano transaction fees, and why tokens need ADA

The formula

How is a Cardano transaction fee calculated?

Cardano charges by the byte. The fee is a x size(tx) + b, where size is the serialised transaction in bytes, b is a flat charge every transaction pays whatever its size, and a is the price of each byte (docs.cardano.org, checked September 11, 2026). The flat part means flooding the chain with tiny transactions still costs the sender something.

Both are protocol parameters. As of September 11, 2026 they are 155,381 lovelace for the base and 44 lovelace per byte, the values set out in CIP-9 and still live on mainnet (Koios epoch parameters). A lovelace is one millionth of an ADA: 0.155381 ADA plus 0.000044 ADA per byte.

Two worked examples. Sizes vary with how many inputs and outputs a wallet uses, so treat the byte counts as illustrations:

1. A plain ADA transfer, about 300 bytes. 155,381 + (44 x 300) = 168,581 lovelace, or 0.168581 ADA. The Cardano developer portal puts a typical simple transfer at 0.17 to 0.20 ADA (developers.cardano.org, checked September 11, 2026).
2. The same transfer carrying one native token, about 400 bytes. 155,381 + (44 x 400) = 172,981 lovelace, or 0.172981 ADA. A token makes the transaction longer, so the fee rises by hundredths of an ADA. That is not where the extra ADA you notice comes from.

A wallet full of small scattered outputs has to spend more of them to make up an amount, lengthening the transaction and raising the fee (developers.cardano.org). No transaction may exceed 16,384 bytes (Koios).

No fee market

Why does the fee not change when the network is busy?

Because there is nothing to bid on. The developer portal puts it plainly: fees "are calculated from a simple linear formula based on transaction size, so you can compute the exact fee before submitting, with no auctions and no gas-price spikes" (developers.cardano.org, checked September 11, 2026). Your wallet computes the same number the node will and shows it before you sign.

Demand shows up as waiting, not as cost: when blocks fill, your transaction sits in the mempool longer but still costs what the formula says. The two numbers can be changed by a governance action altering the protocol parameters (docs.cardano.org), which is a deliberate, occasional event.

Minimum ADA

Why does sending a token need extra ADA?

This is the part that confuses nearly everyone, and the key point is that it is not a fee. Cardano stores balances as outputs, and every output must hold a minimum amount of ADA set by its size. Send a token and you create an output containing it, so that output carries ADA too, and that ADA goes to the recipient with the token.

The rule is set by the coinsPerUTxOByte parameter. The minimum is (160 + the size of the output in bytes) x coinsPerUTxOByte, where the 160 covers the transaction input and the output's entry in the ledger's UTxO map (CIP-55). As of September 11, 2026, coinsPerUTxOByte is 4,310 lovelace (Koios). An output holding nothing but ADA lands near 0.85 ADA; the Cardano command line tools report 857,690 lovelace, a shade above what the ledger accepts (cardano-node issue 4061). Add a token and the output is bigger, so the minimum is higher: the developer portal describes it as roughly 1 to 1.5 ADA depending on contents (developers.cardano.org, checked September 11, 2026).

What raises the minimum is the number of different tokens, not how many units you hold. Ten different tokens in one output, each with its own policy ID and name, need a good deal more than one (Cardano Foundation docs, checked September 11, 2026). The rule caps how much space unspent outputs can take up, since every node keeps all of it in memory. So when a token such as $CATSKY, policy ID 9b426921a21f54600711da0be1a12b026703a9bd8eb9848d08c9d921copy, arrives, roughly an ADA arrives parked alongside it. The native token explainer covers what is being sent.

Locked balance

Why can I not empty my wallet to zero ADA?

Because the tokens must live somewhere, and wherever they live has to hold ADA. Send every last ADA out of a wallet that still holds tokens and there is no legal way to build the transaction: the change output would contain tokens and no ADA, which the ledger rejects. Wallets handle this by showing part of your balance as locked and refusing to spend it.

In our experience this catches people twice: once when a wallet shows twelve ADA but will only send ten and a half, and once when someone sends their last ADA away and then cannot move their tokens, having nothing left to pay a fee with. The fix for both is to leave a few ADA in place. The locked ADA belongs to whoever holds the tokens: it stays yours while they sit in your wallet, and it goes to the recipient if you send them away. None of this is staking, which locks nothing (staking guide).

Smart contracts

Why does a swap on a DEX cost more than a transfer?

A transfer only has to be checked. A smart contract has to be run, and running it is charged for separately. Cardano meters a script in execution units, one budget for memory and one for processor steps, and adds priceMemory x memory units + priceSteps x steps on top of the size fee (developers.cardano.org, checked September 11, 2026). As of September 11, 2026 those prices are 0.0577 lovelace per memory unit and 0.0000721 lovelace per step, and no transaction may use more than 16,500,000 memory units or 10,000,000,000 steps (Koios).

Because those totals depend on what the contract does, there is no fixed price for a swap. Your wallet or the exchange simulates the script before you sign and shows the number. Two other charges can appear. Scripts kept on chain and referenced rather than included are billed from 15 lovelace per byte, rising by a factor of 1.2 per further 25,600 bytes, capped at 200 KiB. And a contract transaction must point at collateral, an ADA-only output worth at least 150% of the fee, returned untouched unless the script fails validation (developers.cardano.org). The exchange's own trading fee sits on top and has nothing to do with the chain; the Minswap guide breaks down which you pay.

Where it goes

Who actually receives my fee?

Not the block producer. Fees from every transaction in every block of an epoch go into a single pot together with a slice of the remaining reserves. Twenty percent of that pot goes to the Cardano treasury before anything else is paid out, and the rest becomes the epoch's rewards, split between stake pools and their delegators (docs.cardano.org, checked September 11, 2026). The pool that minted your block has no special claim on your fee.

Check it yourself

How do I see the exact fee I paid?

Open the transaction on a block explorer. Paste the hash from your wallet's history into Cardanoscan and the page shows a Fees line in ADA, alongside the inputs, the outputs and the size in bytes. Multiply that size by 0.000044, add 0.155381, and for a plain transfer you should land on the same number; any gap is script execution. The guide on reading a Cardano transaction on Cardanoscan covers the rest of that page, and an output holding a token is the quickest way to see the minimum ADA rule for yourself.

Related: all guides · read a transaction on Cardanoscan · swap tokens on Minswap · how to stake ADA