diff --git a/CHANGELOG.md b/CHANGELOG.md
index 45378b80..2fc414dc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,10 @@ CHANGELOG for FlatCAM beta
 
 =================================================
 
+17.08.2021
+
+- made sure that the optimal tool detected works for isolation - the offset amount changed to reflect the number of decimals used by the app
+
 15.08.2021
 
 - fixed some issues with using the exec_() which now should be exec()
diff --git a/appPlugins/ToolIsolation.py b/appPlugins/ToolIsolation.py
index 243f54d2..317303ec 100644
--- a/appPlugins/ToolIsolation.py
+++ b/appPlugins/ToolIsolation.py
@@ -1096,7 +1096,7 @@ class ToolIsolation(AppTool, Gerber):
 
         min_list = list(min_dict.keys())
         min_dist = min(min_list)
-        min_dist -= 0.0001  # make sure that this works for isolation case
+        min_dist -= 10**-decimals  # make sure that this works for isolation case
 
         return msg, min_dist
 
diff --git a/appPlugins/ToolNCC.py b/appPlugins/ToolNCC.py
index 12a2f3a9..ffcae397 100644
--- a/appPlugins/ToolNCC.py
+++ b/appPlugins/ToolNCC.py
@@ -1057,7 +1057,7 @@ class NonCopperClear(AppTool, Gerber):
 
         min_list = list(min_dict.keys())
         min_dist = min(min_list)
-        min_dist -= 0.0001  # make sure that this works for isolation case
+        min_dist -= 10**-decimals  # make sure that this works for isolation case
 
         return msg, min_dist
 
diff --git a/appPlugins/ToolOptimal.py b/appPlugins/ToolOptimal.py
index b9ccee3b..abe77921 100644
--- a/appPlugins/ToolOptimal.py
+++ b/appPlugins/ToolOptimal.py
@@ -257,7 +257,7 @@ class ToolOptimal(AppTool):
 
                 min_list = list(self.min_dict.keys())
                 min_dist = min(min_list)
-                min_dist -= 0.0001  # make sure that this will work for isolation case
+                min_dist -= 10**-self.decimals  # make sure that this will work for isolation case
                 min_dist_string = '%.*f' % (self.decimals, float(min_dist))
                 self.ui.result_entry.set_value(min_dist_string)