diff --git a/catalog_tools/plots/basics.py b/catalog_tools/plots/basics.py
index 20212f7..5122ea8 100644
--- a/catalog_tools/plots/basics.py
+++ b/catalog_tools/plots/basics.py
@@ -111,9 +111,9 @@ def get_cum_fmd(
     mags_i = bin_to_precision(mags / delta_m - np.min(mags / delta_m), 1)
     mags_i = mags_i.astype(int)
     counts = np.bincount(mags_i)
-    bins = bin_to_precision(np.arange((np.min(mags)) * 1000,
-                                      (np.max(mags) + delta_m / 2) * 1000,
-                                      delta_m * 1000) / 1000, delta_m)
+    bins = bin_to_precision(np.arange((np.min(mags)) * 10000,
+                                      (np.max(mags) + delta_m / 2) * 10000,
+                                      delta_m * 10000) / 10000, delta_m)
 
     bins = bins[::-1]
     c_counts = np.cumsum(counts[::-1])
diff --git a/catalog_tools/plots/tests/test_basics.py b/catalog_tools/plots/tests/test_basics.py
index 9b0102a..a74e93a 100644
--- a/catalog_tools/plots/tests/test_basics.py
+++ b/catalog_tools/plots/tests/test_basics.py
@@ -1,7 +1,8 @@
+import pytest
 import numpy as np
 from numpy.testing import assert_allclose
 
-from catalog_tools.plots.basics import dot_size
+from catalog_tools.plots.basics import dot_size, get_cum_fmd
 
 
 def test_dot_size():
@@ -37,3 +38,34 @@ def test_dot_size():
 
     # Check that the computed sizes are close to the expected ones
     assert_allclose(sizes, expected_sizes, rtol=tolerance, atol=tolerance)
+
+
+@pytest.mark.parametrize(
+    "magnitudes, delta_m, bins, c_counts, left",
+    [(np.array([0.20990507, 0.04077336, 0.27906596, 0.57406287, 0.64256544,
+                0.07293118, 0.58589873, 0.02678655, 0.27631233, 0.17682814]),
+      0.1, np.array([0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0]),
+      np.array([3, 3, 3, 5, 7, 8, 10]), False),
+     (np.array([0.02637757, 0.06353823, 0.10257919, 0.54494906, 0.03928375,
+                0.08825028, 0.77713586, 0.54553981, 0.69315583, 0.06656642,
+                0.29035447, 0.2051877, 0.30858087, 0.68896342, 0.03328782,
+                0.45016109, 0.40779409, 0.06788892, 0.02684032, 0.56140282,
+                0.29443359, 0.36328762, 0.17124489, 0.02154936, 0.36461541,
+                0.03613088, 0.15798366, 0.09111875, 0.16169287, 0.11986668,
+                0.10232035, 0.72695761, 0.19484174, 0.0459675, 0.40514163,
+                0.08979514, 0.0442659, 0.18672424, 0.21239088, 0.02287468,
+                0.1244267, 0.04939361, 0.11232758, 0.02706083, 0.04275401,
+                0.02732529, 0.83884229, 0.4147758, 0.07416183, 0.05636252]),
+      0.2, np.array([0.7, 0.5, 0.3, 0.1, -0.1]), np.array([3, 8,
+                                                           15, 29, 50]), True)]
+)
+def test_get_cum_fmd(magnitudes: np.ndarray, delta_m: float,
+                     bins: np.ndarray, c_counts: np.ndarray, left: bool):
+    errors = []
+    nbins, nc_counts, nmags = get_cum_fmd(magnitudes, delta_m, left=left)
+    if not np.allclose(bins, nbins, atol=1e-10):
+        errors.append("Incorrect bin values.")
+    if not np.allclose(c_counts, nc_counts, atol=1e-10):
+        errors.append("Incorrect cumulative counts.")
+
+    assert not errors, "errors occurred:\n{}".format("\n".join(errors))