diff --git a/src/cr39py/filtration/stack.py b/src/cr39py/filtration/stack.py
index 82ec48a..1c9d2a8 100644
--- a/src/cr39py/filtration/stack.py
+++ b/src/cr39py/filtration/stack.py
@@ -202,6 +202,26 @@ def _range_ion(
                 return 0 * E.u
         return E
 
+    def projected_range(self, particle: str, E_in: u.Quantity) -> u.Quantity:
+        """
+        Calculate the projected range of a particle in the layer.
+
+        Parameters
+        ----------
+        particle : str
+            Incident particle
+
+        E_in : u.Quantity
+            Energy of the particle before ranging in the layer.
+
+        Returns
+        -------
+        R : u.Quantity
+            Projected range of the particle in the layer.
+        """
+        prjrng_interp = self.srim_data(particle).projected_range_interpolator
+        return prjrng_interp(E_in.m_as(u.eV)) * u.m
+
     def range_down(
         self,
         particle: str,
diff --git a/src/cr39py/scan/base_scan.py b/src/cr39py/scan/base_scan.py
index b5c9079..2f078b2 100644
--- a/src/cr39py/scan/base_scan.py
+++ b/src/cr39py/scan/base_scan.py
@@ -839,7 +839,8 @@ def chi(self) -> tuple[np.ndarray]:
         return x, y, chi
 
     def F2(self) -> tuple[np.ndarray]:
-        """The Zylstra overlap parameter ``F2`` for each cell.
+        """
+        The Zylstra overlap parameter ``F2`` for each cell.
 
         F2 is the fraction of tracks that overlap one other track, and
         is a reasonable approximation of the number of tracks that will
diff --git a/tests/filtration/test_stack.py b/tests/filtration/test_stack.py
index b48238a..5a7aacf 100644
--- a/tests/filtration/test_stack.py
+++ b/tests/filtration/test_stack.py
@@ -61,6 +61,8 @@ def test_save_layer(tmpdir):
     ("25 um Al", "Triton", 3 * u.MeV, 1.642 * u.MeV),
 ]
 
+# TODO add tests for projected range
+
 
 @pytest.mark.parametrize("layer,particle,Ein,expected", cases)
 def test_layer_ion_ranging(layer, particle, Ein, expected):