diff --git a/esbo_etc/classes/SpectralQty.py b/esbo_etc/classes/SpectralQty.py
index 055ab1a..4100395 100644
--- a/esbo_etc/classes/SpectralQty.py
+++ b/esbo_etc/classes/SpectralQty.py
@@ -4,6 +4,8 @@ import astropy.units as u
 import math
 from typing import Union
 import logging
+from astropy.io import ascii
+import re
 
 
 class SpectralQty:
@@ -11,7 +13,7 @@ class SpectralQty:
     A class to hold and work with spectral quantities
     """
 
-    def __init__(self, wl: u.Quantity, qty: u.Quantity, extrapolate: bool = False):
+    def __init__(self, wl: u.Quantity, qty: u.Quantity, extrapolate: bool = False) -> "SpectralQty":
         """
         Initialize a new spectral quantity
 
@@ -24,6 +26,10 @@ class SpectralQty:
             they are assumed to be dimensionless.
         extrapolate : bool
             Whether extrapolation should be allowed. If disabled, the spectrum will be truncated and a warning given.
+        Returns
+        -------
+        sqty : SpectralQty
+            The created spectral quantity.
         """
         # Check if both lengths are equal
         if len(wl) == len(qty):
@@ -40,6 +46,49 @@ class SpectralQty:
             error("Lengths not matching")
         self._extrapolate = extrapolate
 
+    @classmethod
+    def fromFile(cls, file: str, wl_unit_default: u.Quantity = None, qty_unit_default: u.Quantity = None,
+                 extrapolate: bool = False) -> "SpectralQty":
+        """
+        Initialize a new spectral quantity and read the values from a file
+
+        Parameters
+        ----------
+        file : str
+            Path to the file to read the values from. The file needs to provide two columns: wavelength
+            and the corresponding spectral quantity. The format of the file will be guessed by
+            `astropy.io.ascii.read(). If the file doesn't provide units via astropy's enhanced CSV format, the units
+            will be read from the column headers or otherwise assumed to be *wl_unit_default* and *qty_unit_default*.
+        wl_unit_default : Quantity
+            Default unit to be used for the wavelength column if no units are provided by the file.
+        qty_unit_default : Quantity
+            Default unit to be used for the quantity column if no units are provided by the file.
+        extrapolate : bool
+            Whether extrapolation should be allowed. If disabled, the spectrum will be truncated and a warning given.
+        Returns
+        -------
+        sqty : SpectralQty
+            The created spectral quantity.
+        """
+        # Read the file
+        data = ascii.read(file)
+        # Check if units are given
+        if data[data.colnames[0]].unit is None:
+            # Convert values to float
+            data[data.colnames[0]] = list(map(float, data[data.colnames[0]]))
+            data[data.colnames[1]] = list(map(float, data[data.colnames[1]]))
+            # Check if units are given in column headers
+            if all([re.search("\\[.+\\]", x) for x in data.colnames]):
+                # Extract units from headers and apply them on the columns
+                units = [u.Unit(re.findall("(?<=\\[).+(?=\\])", x)[0]) for x in data.colnames]
+                data[data.colnames[0]].unit = units[0]
+                data[data.colnames[1]].unit = units[1]
+            # Use default units
+            elif wl_unit_default is not None and qty_unit_default is not None:
+                data[data.colnames[0]].unit = wl_unit_default
+                data[data.colnames[1]].unit = qty_unit_default
+        return cls(data[data.colnames[0]].quantity, data[data.colnames[1]].quantity, extrapolate=extrapolate)
+
     def __eq__(self, other) -> bool:
         """
         Check if this object is equal to another object
@@ -59,7 +108,7 @@ class SpectralQty:
                all([math.isclose(x, y, rel_tol=1e-5) for x, y in zip(self.wl.value, other.wl.value)]) and \
                all([math.isclose(x, y, rel_tol=1e-5) for x, y in zip(self.qty.value, other.qty.value)])
 
-    def __add__(self, other: Union[int, float, u.Quantity, "SpectralQty"]):
+    def __add__(self, other: Union[int, float, u.Quantity, "SpectralQty"]) -> "SpectralQty":
         """
         Calculate the sum with another object
 
@@ -103,7 +152,7 @@ class SpectralQty:
 
     __radd__ = __add__
 
-    def __sub__(self, other: Union[int, float, u.Quantity, "SpectralQty"]):
+    def __sub__(self, other: Union[int, float, u.Quantity, "SpectralQty"]) -> "SpectralQty":
         """
         Calculate the difference to another object
 
@@ -145,7 +194,7 @@ class SpectralQty:
             else:
                 error("Units are not matching for substraction.")
 
-    def __mul__(self, other: Union[int, float, u.Quantity, "SpectralQty"]):
+    def __mul__(self, other: Union[int, float, u.Quantity, "SpectralQty"]) -> "SpectralQty":
         """
         Calculate the product with another object
 
diff --git a/tests/test_SpectralQty.py b/tests/test_SpectralQty.py
index 4e10c49..d30890e 100644
--- a/tests/test_SpectralQty.py
+++ b/tests/test_SpectralQty.py
@@ -97,3 +97,14 @@ class TestSpectralQty(TestCase):
         sqty_res = SpectralQty(wl_new[:2], [1.15, 1.35] << u.W / (u.m ** 2 * u.nm))
         sqty_rebin = self.sqty.rebin(wl_new)
         self.assertEqual(sqty_rebin, sqty_res)
+
+    def test_fromFile(self):
+        sqty = SpectralQty.fromFile("data/target/target_demo_1.csv", u.nm, u.W / (u.m ** 2 * u.nm))
+        print(sqty.qty)
+        print(sqty.wl)
+        res = SpectralQty(np.arange(1.1, 2.1, 0.1) * 1e-15 << u.W / (u.m**2 * u.nm),
+                                           np.arange(200, 210, 1) << u.nm)
+        print(res.qty)
+        print(res.wl)
+        self.assertEqual(sqty, SpectralQty(np.arange(200, 210, 1) << u.nm,
+                                           np.arange(1.1, 2.1, 0.1) * 1e-15 << u.W / (u.m**2 * u.nm)))