diff --git a/src/NmeaParser/Nmea/NmeaMessage.cs b/src/NmeaParser/Nmea/NmeaMessage.cs
index 9a634c1..4e2bbf9 100644
--- a/src/NmeaParser/Nmea/NmeaMessage.cs
+++ b/src/NmeaParser/Nmea/NmeaMessage.cs
@@ -65,6 +65,7 @@ namespace NmeaParser.Messages
         {
             MessageType = messageType;
             MessageParts = messageParts;
+            Timestamp = System.Diagnostics.Stopwatch.GetTimestamp() * 1000d / System.Diagnostics.Stopwatch.Frequency;
         }
 
         static NmeaMessage()
@@ -294,5 +295,14 @@ namespace NmeaParser.Messages
             }
             return TimeSpan.Zero;
         }
+
+        /// <summary>
+        /// Gets a relative timestamp in milliseconds indicating the time the message was created.
+        /// </summary>
+        /// <remarks>
+        /// This value is deduced from <c>System.Diagnostics.Stopwatch.GetTimestamp() * 1000d / System.Diagnostics.Stopwatch.Frequency</c>.
+        /// You can use it to calculate the age of the message in seconds by calculating the difference between the timestamp and the above expression
+        /// </remarks>
+        public double Timestamp { get; }
     }
 }
diff --git a/src/NmeaParser/NmeaParser.csproj b/src/NmeaParser/NmeaParser.csproj
index 2e49093..44bce08 100644
--- a/src/NmeaParser/NmeaParser.csproj
+++ b/src/NmeaParser/NmeaParser.csproj
@@ -24,7 +24,8 @@
 Added IGeographicLocation interface to easily get any message that supports reporting a location.
 Added GnssMonitor for simplifying monitoring location messages and reporting a location.
 Added an NTRIP client for getting RTCM correctional messages from an NTRIP Server.
-Improved the buffered stream to more accurately emulate baud rates.</PackageReleaseNotes>
+Improved the buffered stream to more accurately emulate baud rates.
+All messages now have a unique timestamp useful to expire older messages.</PackageReleaseNotes>
     <PublishRepositoryUrl>true</PublishRepositoryUrl>
     <EmbedUntrackedSources>true</EmbedUntrackedSources>
     <AllowedOutputExtensionsInPackageBuildOutputFolder>$(AllowedOutputExtensionsInPackageBuildOutputFolder);.pdb</AllowedOutputExtensionsInPackageBuildOutputFolder>