diff --git a/custom_components/mikrotik_router/mikrotik_controller.py b/custom_components/mikrotik_router/mikrotik_controller.py
index c87bbbf..99c5d80 100644
--- a/custom_components/mikrotik_router/mikrotik_controller.py
+++ b/custom_components/mikrotik_router/mikrotik_controller.py
@@ -1,11 +1,12 @@
 """Mikrotik Controller for Mikrotik Router."""
 
-import re
 import asyncio
-import logging
 import ipaddress
+import logging
+import re
+import pytz
 
-from datetime import timedelta
+from datetime import datetime, timedelta
 from ipaddress import ip_address, IPv4Network
 from mac_vendor_lookup import AsyncMacLookup
 
@@ -61,6 +62,8 @@ from .mikrotikapi import MikrotikAPI
 
 _LOGGER = logging.getLogger(__name__)
 
+DEFAULT_TIME_ZONE = None
+
 
 def is_valid_ip(address):
     try:
@@ -70,6 +73,21 @@ def is_valid_ip(address):
         return False
 
 
+def utc_from_timestamp(timestamp: float) -> datetime:
+    """Return a UTC time from a timestamp."""
+    return pytz.utc.localize(datetime.utcfromtimestamp(timestamp))
+
+
+def as_local(dattim: datetime) -> datetime:
+    """Convert a UTC datetime object to local time zone."""
+    if dattim.tzinfo == DEFAULT_TIME_ZONE:
+        return dattim
+    if dattim.tzinfo is None:
+        dattim = pytz.utc.localize(dattim)
+
+    return dattim.astimezone(DEFAULT_TIME_ZONE)
+
+
 # ---------------------------
 #   MikrotikControllerData
 # ---------------------------
@@ -1215,17 +1233,34 @@ class MikrotikControllerData:
         )
 
         tmp_uptime = 0
-        tmp = re.split(r"(\d+)[h]", self.data["resource"]["uptime_str"])
+        tmp = re.split(r"(\d+)[s]", self.data["resource"]["uptime_str"])
         if len(tmp) > 1:
             tmp_uptime += int(tmp[1])
+        tmp = re.split(r"(\d+)[m]", self.data["resource"]["uptime_str"])
+        if len(tmp) > 1:
+            tmp_uptime += int(tmp[1]) * 60
+        tmp = re.split(r"(\d+)[h]", self.data["resource"]["uptime_str"])
+        if len(tmp) > 1:
+            tmp_uptime += int(tmp[1]) * 3600
         tmp = re.split(r"(\d+)[d]", self.data["resource"]["uptime_str"])
         if len(tmp) > 1:
-            tmp_uptime += int(tmp[1]) * 24
+            tmp_uptime += int(tmp[1]) * 86400
         tmp = re.split(r"(\d+)[w]", self.data["resource"]["uptime_str"])
         if len(tmp) > 1:
-            tmp_uptime += int(tmp[1]) * 24 * 7
+            tmp_uptime += int(tmp[1]) * 604800
 
-        self.data["resource"]["uptime"] = tmp_uptime
+        now = datetime.now().replace(microsecond=0)
+        uptime_tm = datetime.timestamp(now - timedelta(seconds=tmp_uptime))
+        update_uptime = False;
+        if self.data["resource"]["uptime"] is None or self.data["resource"]["uptime"] == 0:
+            update_uptime = True;
+        else:
+            uptime_old = datetime.timestamp(datetime.fromisoformat(self.data["resource"]["uptime"]))
+            if uptime_tm > uptime_old:
+                update_uptime = True;
+
+        if update_uptime:
+            self.data["resource"]["uptime"] = str(as_local(utc_from_timestamp(uptime_tm)).isoformat())
 
         if self.data["resource"]["total-memory"] > 0:
             self.data["resource"]["memory-usage"] = round(
diff --git a/custom_components/mikrotik_router/sensor.py b/custom_components/mikrotik_router/sensor.py
index 92944be..ba96901 100644
--- a/custom_components/mikrotik_router/sensor.py
+++ b/custom_components/mikrotik_router/sensor.py
@@ -8,6 +8,7 @@ from homeassistant.const import (
     ATTR_ATTRIBUTION,
     ATTR_DEVICE_CLASS,
     DEVICE_CLASS_TEMPERATURE,
+    DEVICE_CLASS_TIMESTAMP,
     DEVICE_CLASS_POWER,
     TEMP_CELSIUS,
 )
@@ -107,10 +108,10 @@ SENSOR_TYPES = {
         ATTR_ATTR: "fan2-speed",
     },
     "system_uptime": {
-        ATTR_DEVICE_CLASS: None,
-        ATTR_ICON: "mdi:clock-outline",
+        ATTR_DEVICE_CLASS: DEVICE_CLASS_TIMESTAMP,
+        ATTR_ICON: None,
         ATTR_LABEL: "Uptime",
-        ATTR_UNIT: "h",
+        ATTR_UNIT: None,
         ATTR_GROUP: "System",
         ATTR_PATH: "resource",
         ATTR_ATTR: "uptime",