diff --git a/packages/sdk/CHANGELOG.md b/packages/sdk/CHANGELOG.md
index 621c3778..e130c98d 100644
--- a/packages/sdk/CHANGELOG.md
+++ b/packages/sdk/CHANGELOG.md
@@ -1,5 +1,14 @@
 # Changelog
 
+## Unreleased
+
+## 8.1.1
+
+### Fixed
+
+- `getEnergyCost` returning energy amounts that were off by one due to not including the transaction type in the
+  transaction payload serialization.
+
 ## 8.1.0
 
 ### Added
diff --git a/packages/sdk/package.json b/packages/sdk/package.json
index f4892b4b..0203c653 100644
--- a/packages/sdk/package.json
+++ b/packages/sdk/package.json
@@ -1,6 +1,6 @@
 {
     "name": "@concordium/web-sdk",
-    "version": "8.1.0",
+    "version": "8.1.1",
     "license": "Apache-2.0",
     "engines": {
         "node": ">=16"
diff --git a/packages/sdk/src/accountTransactions.ts b/packages/sdk/src/accountTransactions.ts
index 931b5565..becedab5 100644
--- a/packages/sdk/src/accountTransactions.ts
+++ b/packages/sdk/src/accountTransactions.ts
@@ -49,6 +49,8 @@ export interface AccountTransactionHandler<
 > {
     /**
      * Serializes the payload to a buffer.
+     * This does NOT include the serialized transaction type. To have this included, use {@linkcode serializeAccountTransactionPayload} instead.
+     *
      * @param payload - The payload to serialize.
      * @returns The serialized payload.
      */
diff --git a/packages/sdk/src/energyCost.ts b/packages/sdk/src/energyCost.ts
index 24190dfb..71d72eb1 100644
--- a/packages/sdk/src/energyCost.ts
+++ b/packages/sdk/src/energyCost.ts
@@ -1,5 +1,6 @@
 import { getAccountTransactionHandler } from './accountTransactions.js';
 import { collapseRatio, multiplyRatio } from './ratioHelpers.js';
+import { serializeAccountTransactionPayload } from './serialization.js';
 import { AccountTransactionPayload, AccountTransactionType, ChainParameters, Ratio } from './types.js';
 import * as CcdAmount from './types/CcdAmount.js';
 import * as Energy from './types/Energy.js';
@@ -12,7 +13,7 @@ export const constantA = 100n;
 export const constantB = 1n;
 
 // Account address (32 bytes), nonce (8 bytes), energy (8 bytes), payload size (4 bytes), expiry (8 bytes);
-const accountTransactionHeaderSize = BigInt(32 + 8 + 8 + 4 + 8);
+const ACCOUNT_TRANSACTION_HEADER_SIZE = BigInt(32 + 8 + 8 + 4 + 8);
 
 /**
  * The energy cost is assigned according to the formula:
@@ -30,7 +31,9 @@ export function calculateEnergyCost(
     transactionSpecificCost: bigint
 ): Energy.Type {
     return Energy.create(
-        constantA * signatureCount + constantB * (accountTransactionHeaderSize + payloadSize) + transactionSpecificCost
+        constantA * signatureCount +
+            constantB * (ACCOUNT_TRANSACTION_HEADER_SIZE + payloadSize) +
+            transactionSpecificCost
     );
 }
 
@@ -44,8 +47,8 @@ export function getEnergyCost(
     payload: AccountTransactionPayload,
     signatureCount = 1n
 ): Energy.Type {
+    const size = serializeAccountTransactionPayload({ payload, type: transactionType }).length;
     const handler = getAccountTransactionHandler(transactionType);
-    const size = handler.serialize(payload).length;
     return calculateEnergyCost(signatureCount, BigInt(size), handler.getBaseEnergyCost(payload));
 }
 
diff --git a/packages/sdk/src/serialization.ts b/packages/sdk/src/serialization.ts
index 56cfc3be..2b305190 100644
--- a/packages/sdk/src/serialization.ts
+++ b/packages/sdk/src/serialization.ts
@@ -98,20 +98,18 @@ export function serializeAccountTransaction(
     const serializedBlockItemKind = encodeWord8(BlockItemKind.AccountTransactionKind);
     const serializedAccountTransactionSignatures = serializeAccountTransactionSignature(signatures);
 
-    const serializedType = serializeAccountTransactionType(accountTransaction.type);
-
     const accountTransactionHandler = getAccountTransactionHandler(accountTransaction.type);
-    const serializedPayload = accountTransactionHandler.serialize(accountTransaction.payload);
+    const serializedPayload = serializeAccountTransactionPayload(accountTransaction);
 
     const baseEnergyCost = accountTransactionHandler.getBaseEnergyCost(accountTransaction.payload);
     const energyCost = calculateEnergyCost(
         countSignatures(signatures),
-        BigInt(serializedPayload.length + 1),
+        BigInt(serializedPayload.length),
         baseEnergyCost
     );
     const serializedHeader = serializeAccountTransactionHeader(
         accountTransaction.header,
-        serializedPayload.length + 1,
+        serializedPayload.length,
         energyCost
     );
 
@@ -119,7 +117,6 @@ export function serializeAccountTransaction(
         serializedBlockItemKind,
         serializedAccountTransactionSignatures,
         serializedHeader,
-        serializedType,
         serializedPayload,
     ]);
 }
@@ -129,7 +126,7 @@ export function serializeAccountTransaction(
  * @param accountTransaction the transaction which payload is to be serialized
  * @returns the account transaction payload serialized as a buffer.
  */
-export function serializeAccountTransactionPayload(accountTransaction: AccountTransaction): Buffer {
+export function serializeAccountTransactionPayload(accountTransaction: Omit<AccountTransaction, 'header'>): Buffer {
     const serializedType = serializeAccountTransactionType(accountTransaction.type);
 
     const accountTransactionHandler = getAccountTransactionHandler(accountTransaction.type);
@@ -160,17 +157,17 @@ export function getAccountTransactionHash(
  */
 export function getAccountTransactionSignDigest(accountTransaction: AccountTransaction, signatureCount = 1n): Buffer {
     const accountTransactionHandler = getAccountTransactionHandler(accountTransaction.type);
-    const serializedPayload = accountTransactionHandler.serialize(accountTransaction.payload);
+    const serializedPayload = serializeAccountTransactionPayload(accountTransaction);
 
     const baseEnergyCost = accountTransactionHandler.getBaseEnergyCost(accountTransaction.payload);
-    const energyCost = calculateEnergyCost(signatureCount, BigInt(serializedPayload.length + 1), baseEnergyCost);
+    const energyCost = calculateEnergyCost(signatureCount, BigInt(serializedPayload.length), baseEnergyCost);
     const serializedHeader = serializeAccountTransactionHeader(
         accountTransaction.header,
-        serializedPayload.length + 1,
+        serializedPayload.length,
         energyCost
     );
 
-    return sha256([serializedHeader, serializeAccountTransactionType(accountTransaction.type), serializedPayload]);
+    return sha256([serializedHeader, serializedPayload]);
 }
 
 /**