diff --git a/layout/html/table/src/BasicTableLayoutStrategy.cpp b/layout/html/table/src/BasicTableLayoutStrategy.cpp
index 5749485f6b8e..b04c251d002d 100644
--- a/layout/html/table/src/BasicTableLayoutStrategy.cpp
+++ b/layout/html/table/src/BasicTableLayoutStrategy.cpp
@@ -1320,7 +1320,7 @@ BasicTableLayoutStrategy::CalcPctAdjTableWidth(nsIPresContext&          aPresCon
   }
   // If there is only one col and it is % based, it won't affect anything
   if ((1 == numCols) && (numCols == numPerCols)) {
-    return basis; 
+    return basis + borderPadding.left + borderPadding.right + mCellSpacingTotal;
   }
 
   // compute a basis considering total percentages and the desired width of everything else
diff --git a/layout/tables/BasicTableLayoutStrategy.cpp b/layout/tables/BasicTableLayoutStrategy.cpp
index 5749485f6b8e..b04c251d002d 100644
--- a/layout/tables/BasicTableLayoutStrategy.cpp
+++ b/layout/tables/BasicTableLayoutStrategy.cpp
@@ -1320,7 +1320,7 @@ BasicTableLayoutStrategy::CalcPctAdjTableWidth(nsIPresContext&          aPresCon
   }
   // If there is only one col and it is % based, it won't affect anything
   if ((1 == numCols) && (numCols == numPerCols)) {
-    return basis; 
+    return basis + borderPadding.left + borderPadding.right + mCellSpacingTotal;
   }
 
   // compute a basis considering total percentages and the desired width of everything else