diff --git a/src/EditorFeatures/Core/Copilot/RoslynProposalAdjusterProvider.cs b/src/EditorFeatures/Core/Copilot/RoslynProposalAdjusterProvider.cs
index f45fcc2ae5f46..f82a7549749cd 100644
--- a/src/EditorFeatures/Core/Copilot/RoslynProposalAdjusterProvider.cs
+++ b/src/EditorFeatures/Core/Copilot/RoslynProposalAdjusterProvider.cs
@@ -5,6 +5,7 @@
 using System;
 using System.Collections.Generic;
 using System.ComponentModel.Composition;
+using System.Globalization;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
@@ -41,7 +42,7 @@ private static void SetDefaultTelemetryProperties(Dictionary<string, object?> ma
         // Common properties that all adjustments will log.
         map["ProviderName"] = providerName;
         map["AdjustProposalBeforeDisplay"] = before;
-        map["ComputationTime"] = elapsedTime.TotalMilliseconds.ToString("G17");
+        map["ComputationTime"] = elapsedTime.TotalMilliseconds.ToString("G17", CultureInfo.InvariantCulture);
     }
 
     private async Task<ProposalBase> AdjustProposalAsync(
diff --git a/src/Features/Core/Portable/Copilot/CopilotChangeAnalysisUtilities.cs b/src/Features/Core/Portable/Copilot/CopilotChangeAnalysisUtilities.cs
index e93fa3ccdd212..fe4b2e5631080 100644
--- a/src/Features/Core/Portable/Copilot/CopilotChangeAnalysisUtilities.cs
+++ b/src/Features/Core/Portable/Copilot/CopilotChangeAnalysisUtilities.cs
@@ -5,6 +5,7 @@
 using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
+using System.Globalization;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
@@ -116,7 +117,7 @@ private static string Stringify<TValue>(TValue value) where TValue : notnull
             return string.Join(":", strings.OrderBy(v => v));
 
         if (value is TimeSpan timeSpan)
-            return timeSpan.TotalMilliseconds.ToString("G17");
+            return timeSpan.TotalMilliseconds.ToString("G17", CultureInfo.InvariantCulture);
 
         return value.ToString() ?? "";
     }