Cardano protocol parameters control the behavior of the network, including fees, block sizes, staking mechanics, and governance. These parameters can be queried from a running node and updated through governance actions.
torsten-cli query protocol-parameters \
--socket-path ./node.sock \
--out-file protocol-params.json
Parameter JSON Key Description Mainnet Default
Min fee coefficient txFeePerByte / minFeeAFee per byte of transaction size 44 Min fee constant txFeeFixed / minFeeBFixed fee component 155381 Min UTxO value per byte utxoCostPerByte / adaPerUtxoByteMinimum lovelace per byte of UTxO 4310
The transaction fee formula is:
fee = txFeePerByte * tx_size_in_bytes + txFeeFixed
Parameter JSON Key Description Mainnet Default
Max block body size maxBlockBodySizeMaximum block body size in bytes 90112 Max transaction size maxTxSizeMaximum transaction size in bytes 16384 Max block header size maxBlockHeaderSizeMaximum block header size in bytes 1100
Parameter JSON Key Description Mainnet Default
Stake address deposit stakeAddressDeposit / keyDepositDeposit for stake key registration (lovelace) 2000000 Pool deposit stakePoolDeposit / poolDepositDeposit for pool registration (lovelace) 500000000 Pool retire max epoch poolRetireMaxEpoch / eMaxMaximum future epochs for pool retirement 18 Pool target count stakePoolTargetNum / nOptTarget number of pools (k parameter) 500 Min pool cost minPoolCostMinimum fixed pool cost (lovelace) 170000000
Parameter Description
Monetary expansion (rho) Rate of new ADA creation from reserves per epoch Treasury cut (tau) Fraction of rewards directed to the treasury Pledge influence (a0) How pledge affects reward calculations
Parameter JSON Key Description Mainnet Default
Max tx execution units maxTxExecutionUnits{memory, steps} per transaction{14000000, 10000000000}Max block execution units maxBlockExecutionUnits{memory, steps} per block{62000000, 40000000000}Max value size maxValueSizeMaximum serialized value size in bytes 5000 Collateral percentage collateralPercentageCollateral % of total tx fee for Plutus txs 150 Max collateral inputs maxCollateralInputsMaximum collateral inputs per tx 3
Parameter JSON Key Description Mainnet Default
DRep deposit drepDepositDeposit for DRep registration (lovelace) 500000000 Gov action deposit govActionDepositDeposit for governance action submission (lovelace) 100000000000 Gov action lifetime govActionLifetimeGovernance action expiry (epochs) 6
Different governance action types require different voting thresholds from DReps, SPOs, and the Constitutional Committee:
Action Type DRep Threshold SPO Threshold CC Threshold
No Confidence dvtMotionNoConfidence pvtMotionNoConfidence Required Update Committee (normal) dvtCommitteeNormal pvtCommitteeNormal N/A Update Committee (no confidence) dvtCommitteeNoConfidence pvtCommitteeNoConfidence N/A New Constitution dvtUpdateToConstitution N/A Required Hard Fork Initiation dvtHardForkInitiation pvtHardForkInitiation Required Protocol Parameter Update (network) dvtPPNetworkGroup N/A Required Protocol Parameter Update (economic) dvtPPEconomicGroup pvtPPEconomicGroup Required Protocol Parameter Update (technical) dvtPPTechnicalGroup N/A Required Protocol Parameter Update (governance) dvtPPGovGroup N/A Required Treasury Withdrawal dvtTreasuryWithdrawal N/A Required
When encoding protocol parameter updates in governance actions, each parameter maps to a CBOR field number:
CBOR Key Parameter
0 txFeePerByte / minFeeA 1 txFeeFixed / minFeeB 2 maxBlockBodySize 3 maxTxSize 4 maxBlockHeaderSize 5 stakeAddressDeposit / keyDeposit 6 stakePoolDeposit / poolDeposit 7 poolRetireMaxEpoch / eMax 8 stakePoolTargetNum / nOpt 16 minPoolCost 17 utxoCostPerByte / adaPerUtxoByte 20 maxTxExecutionUnits 21 maxBlockExecutionUnits 22 maxValueSize 23 collateralPercentage 24 maxCollateralInputs 30 drepDeposit 31 govActionDeposit 32 govActionLifetime