diff --git a/ctapipe/image/leakage.py b/ctapipe/image/leakage.py
index 7405b8c901a..2f0d1fde0a1 100644
--- a/ctapipe/image/leakage.py
+++ b/ctapipe/image/leakage.py
@@ -3,8 +3,8 @@
 """
 
 import numpy as np
-from ..containers import LeakageContainer
 
+from ..containers import LeakageContainer
 
 __all__ = ["leakage_parameters"]
 
@@ -40,11 +40,13 @@ def leakage_parameters(geom, image, cleaning_mask):
     leakage_intensity1 = np.sum(image[mask1])
     leakage_intensity2 = np.sum(image[mask2])
 
-    size = np.sum(image[cleaning_mask])
+    clean = image[cleaning_mask]
+    n_pixels_cleaning = len(clean)
+    n_pe_cleaning = np.sum(clean)
 
     return LeakageContainer(
-        pixels_width_1=leakage_pixel1 / geom.n_pixels,
-        pixels_width_2=leakage_pixel2 / geom.n_pixels,
-        intensity_width_1=leakage_intensity1 / size,
-        intensity_width_2=leakage_intensity2 / size,
+        pixels_width_1=leakage_pixel1 / n_pixels_cleaning,
+        pixels_width_2=leakage_pixel2 / n_pixels_cleaning,
+        intensity_width_1=leakage_intensity1 / n_pe_cleaning,
+        intensity_width_2=leakage_intensity2 / n_pe_cleaning,
     )
diff --git a/ctapipe/image/tests/test_leakage.py b/ctapipe/image/tests/test_leakage.py
index 28c2913dc13..44502fa4e2b 100644
--- a/ctapipe/image/tests/test_leakage.py
+++ b/ctapipe/image/tests/test_leakage.py
@@ -1,7 +1,95 @@
 import numpy as np
+import pytest
 
+from ctapipe.containers import LeakageContainer
+from ctapipe.instrument import CameraGeometry
 
-def test_leakage(prod5_lst):
+# simple dummy test cases
+geometry = CameraGeometry.make_rectangular(5, 5)
+image_no_leakage = np.array(
+    [
+        [0, 0, 0, 0, 0],
+        [0, 0, 0, 0, 0],
+        [0, 0, 1, 0, 0],
+        [0, 0, 0, 0, 0],
+        [0, 0, 0, 0, 0],
+    ]
+).ravel()
+container_no_leakage = LeakageContainer(
+    pixels_width_1=0.0,
+    pixels_width_2=0.0,
+    intensity_width_1=0.0,
+    intensity_width_2=0.0,
+)
+
+image_leakage_2_1 = np.array(
+    [
+        [0, 0, 0, 0, 0],
+        [0, 1, 1, 1, 0],
+        [0, 1, 8, 1, 0],
+        [0, 1, 1, 1, 0],
+        [0, 0, 0, 0, 0],
+    ]
+).ravel()
+container_leakage_2_1 = LeakageContainer(
+    pixels_width_1=0.0,
+    pixels_width_2=8 / 9,
+    intensity_width_1=0.0,
+    intensity_width_2=0.5,
+)
+
+image_leakage_2_2 = np.array(
+    [
+        [0, 0, 0, 0, 0],
+        [0, 0, 0, 0, 0],
+        [0, 0, 9, 1, 0],
+        [0, 0, 0, 2, 0],
+        [0, 0, 0, 0, 0],
+    ]
+).ravel()
+container_leakage_2_2 = LeakageContainer(
+    pixels_width_1=0.0,
+    pixels_width_2=2 / 3,
+    intensity_width_1=0.0,
+    intensity_width_2=0.25,
+)
+
+image_leakage_1 = np.array(
+    [
+        [0, 0, 0, 0, 0],
+        [0, 4, 1, 0, 0],
+        [0, 1, 9, 2, 0],
+        [0, 0, 2, 3, 1],
+        [0, 0, 0, 1, 2],
+    ]
+).ravel()
+container_leakage_1 = LeakageContainer(
+    pixels_width_1=3 / 10,
+    pixels_width_2=9 / 10,
+    intensity_width_1=4 / 26,
+    intensity_width_2=17 / 26,
+)
+
+images = (image_no_leakage, image_leakage_2_1, image_leakage_2_2, image_leakage_1)
+containers = (
+    container_no_leakage,
+    container_leakage_2_1,
+    container_leakage_2_2,
+    container_leakage_1,
+)
+
+
+@pytest.mark.parametrize("image,expected", zip(images, containers))
+def test_leakage_toy(image, expected):
+    from ctapipe.image.leakage import leakage_parameters
+
+    leakage = leakage_parameters(geometry, image, image > 0)
+
+    for key, val in expected.items():
+        assert leakage[key] == val, f"{key} does not match"
+
+
+def test_leakage_lst(prod5_lst):
     from ctapipe.image.leakage import leakage_parameters
 
     geom = prod5_lst.camera.geometry
diff --git a/docs/changes/2432.api.rst b/docs/changes/2432.api.rst
new file mode 100644
index 00000000000..d41bacacd6f
--- /dev/null
+++ b/docs/changes/2432.api.rst
@@ -0,0 +1,3 @@
+Change the definition of the ``leakage_pixels_width_{1,2}`` image features
+to give the ratio of pixels at the border to the pixels after cleaning
+instead of to the total number of pixels of the camera.