diff --git a/src/createRollup.ts b/src/createRollup.ts
index 0112c2e3..470e4093 100644
--- a/src/createRollup.ts
+++ b/src/createRollup.ts
@@ -178,7 +178,7 @@ export async function createRollup<TChain extends Chain | undefined>({
   });
   const maxFeePerGas = nativeTokenDecimalsTo18Decimals({
     amount: params.maxFeePerGasForRetryables ?? createRollupDefaults.maxFeePerGasForRetryables,
-    decimals,
+    decimals: Number(decimals),
   });
 
   // prepare the transaction for deploying the core contracts
diff --git a/src/createRollupPrepareTransactionRequest.ts b/src/createRollupPrepareTransactionRequest.ts
index 860d66d9..f8a1a2a8 100644
--- a/src/createRollupPrepareTransactionRequest.ts
+++ b/src/createRollupPrepareTransactionRequest.ts
@@ -110,7 +110,7 @@ export async function createRollupPrepareTransactionRequest<TChain extends Chain
     });
     paramsWithDefaults.maxFeePerGasForRetryables = scaleToNativeTokenDecimals({
       amount: paramsWithDefaults.maxFeePerGasForRetryables,
-      decimals,
+      decimals: Number(decimals),
     });
   }
 
diff --git a/src/createTokenBridge.integration.test.ts b/src/createTokenBridge.integration.test.ts
index c40fcd3e..66dc038a 100644
--- a/src/createTokenBridge.integration.test.ts
+++ b/src/createTokenBridge.integration.test.ts
@@ -105,7 +105,7 @@ async function checkWethGateways(
   expect(tokenBridgeContracts.orbitChainContracts.wethGateway).not.toEqual(zeroAddress);
 }
 
-const nativeTokenDecimals = Number(process.env.DECIMALS) ?? 18;
+const nativeTokenDecimals = process.env.DECIMALS ? Number(process.env.DECIMALS) : 18;
 
 describe('createTokenBridge utils function', () => {
   it(`successfully deploys token bridge contracts through token bridge creator`, async () => {
diff --git a/src/createTokenBridgeEnoughCustomFeeTokenAllowance.ts b/src/createTokenBridgeEnoughCustomFeeTokenAllowance.ts
index 9bcc372e..d0cc72c8 100644
--- a/src/createTokenBridgeEnoughCustomFeeTokenAllowance.ts
+++ b/src/createTokenBridgeEnoughCustomFeeTokenAllowance.ts
@@ -35,6 +35,9 @@ export async function createTokenBridgeEnoughCustomFeeTokenAllowance<
   const decimals = await getNativeTokenDecimals({ publicClient, nativeTokenAddress: nativeToken });
   return (
     allowance >=
-    scaleToNativeTokenDecimals({ amount: createTokenBridgeDefaultRetryablesFees, decimals })
+    scaleToNativeTokenDecimals({
+      amount: createTokenBridgeDefaultRetryablesFees,
+      decimals: Number(decimals),
+    })
   );
 }