diff --git a/cmd/rpcdaemon/commands/zkevm_api.go b/cmd/rpcdaemon/commands/zkevm_api.go
index 6f50ce40351..c1b45e4857d 100644
--- a/cmd/rpcdaemon/commands/zkevm_api.go
+++ b/cmd/rpcdaemon/commands/zkevm_api.go
@@ -14,13 +14,12 @@ import (
 
 	"github.com/holiman/uint256"
 	"github.com/ledgerwatch/erigon/common/hexutil"
-	"github.com/ledgerwatch/erigon/common/u256"
+	"github.com/ledgerwatch/erigon/core"
 	eritypes "github.com/ledgerwatch/erigon/core/types"
 	"github.com/ledgerwatch/erigon/rpc"
 	"github.com/ledgerwatch/erigon/sync_stages"
 	"github.com/ledgerwatch/erigon/zk/hermez_db"
 	types "github.com/ledgerwatch/erigon/zk/rpcdaemon"
-	zktypes "github.com/ledgerwatch/erigon/zk/types"
 	"github.com/ledgerwatch/erigon/zkevm/jsonrpc/client"
 )
 
@@ -534,13 +533,8 @@ func convertReceipt(
 	}
 
 	var effectiveGasPrice *types.ArgBig
-	gas := gasPrice.Clone()
-	if effectiveGasPricePercentage > zktypes.EFFECTIVE_GAS_PRICE_PERCENTAGE_DISABLED && gasPrice != nil {
-		clone := gasPrice.Clone()
-		effectiveGasPricePerc := new(uint256.Int).SetUint64(uint64(effectiveGasPricePercentage))
-		effectiveGasPricePerc.Add(effectiveGasPricePerc, u256.Num1)
-		clone.Mul(clone, effectiveGasPricePerc)
-		gas.Div(clone, zktypes.EFFECTIVE_GAS_PRICE_MAX_VAL)
+	if gasPrice != nil {
+		gas := core.CalculateEffectiveGas(gasPrice, effectiveGasPricePercentage)
 		asBig := types.ArgBig(*gas.ToBig())
 		effectiveGasPrice = &asBig
 	}
diff --git a/core/state_transition.go b/core/state_transition.go
index cde726e2b76..931eca0a651 100644
--- a/core/state_transition.go
+++ b/core/state_transition.go
@@ -157,14 +157,9 @@ func NewStateTransition(evm vm.VMInterface, msg Message, gp *GasPool) *StateTran
 
 	gas := msg.GasPrice()
 
-	// check if we have an effective gas price percentage in the message and apply it
-	ep := msg.EffectiveGasPricePercentage()
-	if ep > zktypes.EFFECTIVE_GAS_PRICE_PERCENTAGE_DISABLED {
-		val := gas.Clone()
-		epi := new(uint256.Int).SetUint64(uint64(ep))
-		epi = epi.Add(epi, u256.Num1)
-		val = val.Mul(val, epi)
-		gas = gas.Div(val, zktypes.EFFECTIVE_GAS_PRICE_MAX_VAL)
+	if evm.ChainRules().IsMordor {
+		ep := msg.EffectiveGasPricePercentage()
+		gas = CalculateEffectiveGas(gas, ep)
 	}
 
 	return &StateTransition{
@@ -185,6 +180,16 @@ func NewStateTransition(evm vm.VMInterface, msg Message, gp *GasPool) *StateTran
 	}
 }
 
+func CalculateEffectiveGas(gas *uint256.Int, ep uint8) *uint256.Int {
+	val := gas.Clone()
+	epi := new(uint256.Int).SetUint64(uint64(ep))
+	epi = epi.Add(epi, u256.Num1)
+	val = val.Mul(val, epi)
+	gas = gas.Div(val, zktypes.EFFECTIVE_GAS_PRICE_MAX_VAL)
+
+	return gas
+}
+
 // ApplyMessage computes the new state by applying the given message
 // against the old state within the environment.
 //