diff --git a/src/backends/meta-monitor.c b/src/backends/meta-monitor.c
index e4e803672..5fc8b1f85 100644
--- a/src/backends/meta-monitor.c
+++ b/src/backends/meta-monitor.c
@@ -1767,7 +1767,8 @@ meta_monitor_mode_should_be_advertised (MetaMonitorMode *monitor_mode)
 static float
 get_closest_scale_factor_for_resolution (float width,
                                          float height,
-                                         float scale)
+                                         float scale,
+                                         float threshold)
 {
   unsigned int i, j;
   float scaled_h;
@@ -1799,8 +1800,8 @@ get_closest_scale_factor_for_resolution (float width,
           current_scale = width / scaled_w;
           scaled_h = height / current_scale;
 
-          if (current_scale >= scale + SCALE_FACTORS_STEPS ||
-              current_scale <= scale - SCALE_FACTORS_STEPS ||
+          if (current_scale >= scale + threshold ||
+              current_scale <= scale - threshold ||
               current_scale < MINIMUM_SCALE_FACTOR ||
               current_scale > MAXIMUM_SCALE_FACTOR)
             {
@@ -1851,14 +1852,22 @@ meta_monitor_calculate_supported_scales (MetaMonitor                 *monitor,
         }
       else
         {
+          float max_bound;
+
+          if (i == floorf (MINIMUM_SCALE_FACTOR) ||
+              i == ceilf (MAXIMUM_SCALE_FACTOR))
+            max_bound = SCALE_FACTORS_STEPS;
+          else
+            max_bound = SCALE_FACTORS_STEPS / 2.0;
+
           for (j = 0; j < SCALE_FACTORS_PER_INTEGER; j++)
             {
               float scale;
               float scale_value = i + j * SCALE_FACTORS_STEPS;
 
               scale = get_closest_scale_factor_for_resolution (width, height,
-                                                               scale_value);
-
+                                                               scale_value,
+                                                               max_bound);
               if (scale > 0.0)
                 g_array_append_val (supported_scales, scale);
             }
diff --git a/src/tests/monitor-test-utils.c b/src/tests/monitor-test-utils.c
index 00823d22f..c5e838c85 100644
--- a/src/tests/monitor-test-utils.c
+++ b/src/tests/monitor-test-utils.c
@@ -811,6 +811,13 @@ check_expected_scales (MetaMonitor                 *monitor,
           g_assert_cmpfloat (fmodf (width / scales[i], 1.0), ==, 0.0);
           g_assert_cmpfloat (fmodf (height / scales[i], 1.0), ==, 0.0);
         }
+
+      if (i > 0)
+        {
+          /* And that scales are sorted and unique */
+          g_assert_cmpfloat (scales[i], >, scales[i-1]);
+          g_assert_false (G_APPROX_VALUE (scales[i], scales[i-1], 0.000001));
+        }
     }
 }
 
diff --git a/src/tests/monitor-unit-tests.c b/src/tests/monitor-unit-tests.c
index 06b170318..d7d3fdc35 100644
--- a/src/tests/monitor-unit-tests.c
+++ b/src/tests/monitor-unit-tests.c
@@ -6273,9 +6273,9 @@ meta_test_monitor_supported_fractional_scales (void)
             {
               .width = 4096,
               .height = 2160,
-              .n_scales = 10,
+              .n_scales = 8,
               .scales = { 1.000000, 1.333333, 1.454545, 1.777778, 2.000000,
-                          2.666667, 2.666667, 3.200000, 3.200000, 4.000000
+                          2.666667, 3.200000, 4.000000
               }
             },
             {