diff --git a/.coveragerc b/.coveragerc
new file mode 100644
index 00000000..fd5df4bf
--- /dev/null
+++ b/.coveragerc
@@ -0,0 +1,5 @@
+[report]
+exclude_lines =
+    pragma: no cover
+    if TYPE_CHECKING.*:
+    \.\.\.
diff --git a/MANIFEST.in b/MANIFEST.in
index 97dc9c8c..1b7a4eb9 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -1,6 +1,7 @@
 include CITATION
 include LICENSE
 
+exclude .coveragerc
 exclude *.yaml
 exclude *.yml
 exclude tox.ini
diff --git a/docs/source/changes.rst b/docs/source/changes.rst
index 42a92864..e3d19f6d 100644
--- a/docs/source/changes.rst
+++ b/docs/source/changes.rst
@@ -36,6 +36,7 @@ all releases are available on `PyPI <https://pypi.org/project/pytask>`_ and
   pytask.
 - :gh:`208` fixes the best practices guide for parametrizations.
 - :gh:`209` cancels previous CI runs automatically.
+- :gh:`212` add ``.coveragerc`` and improve coverage.
 
 
 0.1.5 - 2022-01-10
diff --git a/src/_pytask/profile.py b/src/_pytask/profile.py
index 0da72b25..3e89aa37 100644
--- a/src/_pytask/profile.py
+++ b/src/_pytask/profile.py
@@ -232,7 +232,7 @@ def _to_human_readable_size(bytes_: int, units: list[str] | None = None) -> str:
     units = [" bytes", " KB", " MB", " GB", " TB"] if units is None else units
     return (
         str(bytes_) + units[0]
-        if bytes_ < 1024
+        if bytes_ < 1024 or len(units) == 1
         else _to_human_readable_size(bytes_ >> 10, units[1:])
     )
 
diff --git a/tests/test_profile.py b/tests/test_profile.py
index fbb8904f..ff7a6efb 100644
--- a/tests/test_profile.py
+++ b/tests/test_profile.py
@@ -7,6 +7,7 @@
 from _pytask.cli import cli
 from _pytask.database import create_database
 from _pytask.outcomes import ExitCode
+from _pytask.profile import _to_human_readable_size
 from _pytask.profile import Runtime
 from pony import orm
 from pytask import main
@@ -66,7 +67,12 @@ def task_example(): time.sleep(2)
 def test_profile_if_there_is_information_on_collected_tasks(tmp_path, runner):
     source = """
     import time
-    def task_example(): time.sleep(2)
+    import pytask
+
+    @pytask.mark.produces("out.txt")
+    def task_example(produces):
+        time.sleep(2)
+        produces.write_text("There are nine billion bicycles in Beijing.")
     """
     tmp_path.joinpath("task_example.py").write_text(textwrap.dedent(source))
 
@@ -78,6 +84,8 @@ def task_example(): time.sleep(2)
     assert "Collected 1 task." in result.output
     assert "Duration (in s)" in result.output
     assert "0." in result.output
+    assert "Size of Products" in result.output
+    assert "43 bytes" in result.output
 
 
 @pytest.mark.end_to_end
@@ -99,3 +107,17 @@ def task_example(): time.sleep(2)
     assert "Duration (in s)" in result.output
     assert "0." in result.output
     assert tmp_path.joinpath(f"profile.{export}").exists()
+
+
+@pytest.mark.parametrize(
+    "bytes_, units, expected",
+    [
+        (2**10, None, "1 KB"),
+        (2**20, None, "1 MB"),
+        (2**30, None, "1 GB"),
+        (2**30, [" bytes", " KB", " MB"], "1024 MB"),
+    ],
+)
+def test_to_human_readable_size(bytes_, units, expected):
+    result = _to_human_readable_size(bytes_, units)
+    assert result == expected