diff --git a/ConeCalorimeter/ViewModels/RealtimeDataRowViewModel.cs b/ConeCalorimeter/ViewModels/RealtimeDataRowViewModel.cs
index a8d9dd6..ca1b757 100644
--- a/ConeCalorimeter/ViewModels/RealtimeDataRowViewModel.cs
+++ b/ConeCalorimeter/ViewModels/RealtimeDataRowViewModel.cs
@@ -25,7 +25,7 @@ public sealed class RealtimeDataRowViewModel
         MlrText = Format(record.MassLossRate);
         HeatReleaseText = Format(record.HeatReleaseRateKw);
         EhcText = Format(record.EffectiveHeatOfCombustion);
-        MassLossText = Format(record.MassLoss);
+        MassLossText = FormatAbsolute(record.MassLoss);
     }
 
     public string TimeText { get; init; } = string.Empty;
@@ -62,4 +62,9 @@ public sealed class RealtimeDataRowViewModel
     {
         return double.IsFinite(value) ? value.ToString(format, CultureInfo.InvariantCulture) : string.Empty;
     }
+
+    private static string FormatAbsolute(double value, string format = "0.00")
+    {
+        return double.IsFinite(value) ? Math.Abs(value).ToString(format, CultureInfo.InvariantCulture) : string.Empty;
+    }
 }