diff --git a/midealocal/crc8.py b/midealocal/crc8.py
index 3d56f2d2..036f30da 100644
--- a/midealocal/crc8.py
+++ b/midealocal/crc8.py
@@ -1,4 +1,6 @@
-crc8_854_table = [
+"""CRC8 calculator."""
+
+crc8_854_table: list[int] = [
     0x00,
     0x5E,
     0xBC,
@@ -258,13 +260,12 @@
 ]
 
 
-def calculate(data):
-    crc_value = 0
+def calculate(data: bytearray) -> int:
+    """
+    Calculate CRC8 value of a bytearray.
+
+    """
+    crc_value: int = 0
     for m in data:
-        k = crc_value ^ m
-        if k > 256:
-            k -= 256
-        if k < 0:
-            k += 256
-        crc_value = crc8_854_table[k]
+        crc_value = crc8_854_table[crc_value ^ m]
     return crc_value
diff --git a/tests/crc8_test.py b/tests/crc8_test.py
index 2e969033..5eed5713 100644
--- a/tests/crc8_test.py
+++ b/tests/crc8_test.py
@@ -7,54 +7,12 @@ def test_calculate() -> None:
     """Test calculate method."""
     data: bytearray = bytearray(
         [
-            # 2 bytes - StaicHeader
             0x5A,
-            0x5A,
-            # 2 bytes - mMessageType
+            0x82,
             0x01,
             0x11,
-            # 2 bytes - PacketLenght
-            0x00,
-            0x00,
-            # 2 bytes
+            0xFF,
             0x20,
-            0x00,
-            # 4 bytes - MessageId
-            0x00,
-            0x00,
-            0x00,
-            0x00,
-            # 8 bytes - Date&Time
-            0x00,
-            0x00,
-            0x00,
-            0x00,
-            0x00,
-            0x00,
-            0x00,
-            0x00,
-            # 6 bytes - mDeviceID
-            0x00,
-            0x00,
-            0x00,
-            0x00,
-            0x00,
-            0x00,
-            0x00,
-            0x00,
-            # 12 bytes
-            0x00,
-            0x00,
-            0x00,
-            0x00,
-            0x00,
-            0x00,
-            0x00,
-            0x00,
-            0x00,
-            0x00,
-            0x00,
-            0x00,
         ]
     )
-    assert calculate(data) == 86
+    assert calculate(data) == 101