diff --git a/generate/__init__.py b/generate/__init__.py
new file mode 100644
index 0000000..3584e8b
--- /dev/null
+++ b/generate/__init__.py
@@ -0,0 +1 @@
+"""Package used for auto generating the boilerplate in the quantities."""
diff --git a/generate/generate_boilerplate.py b/generate/generate_boilerplate.py
new file mode 100644
index 0000000..55080e0
--- /dev/null
+++ b/generate/generate_boilerplate.py
@@ -0,0 +1,128 @@
+from __future__ import annotations
+
+from pathlib import Path
+
+TARGET_FILE_PATH = Path(__file__).parent.parent / "quantio" / "quantities.py"
+
+
+def generate_boilerplate(quantities_with_fields: dict[str, dict[str, str]]) -> None:
+    """Generate the boilerplate parts of the quantity classes."""
+    with TARGET_FILE_PATH.open() as target_file:
+        target_content = target_file.readlines()
+
+    target_content_with_boilerplate = []
+    current_class: str | None = None
+
+    current_line_is_part_of_autogenerated_code = False
+    for line in target_content:
+        if line.startswith("class "):
+            current_class = line.split("(")[0][6:]
+
+        if "# --- This part is auto generated. Do not change manually. ---" in line:
+            current_line_is_part_of_autogenerated_code = True
+            target_content_with_boilerplate.append(line)
+            target_content_with_boilerplate.extend(
+                _generate_init(quantities_with_fields[current_class])
+            )
+            target_content_with_boilerplate.extend(
+                _generate_properties(current_class, quantities_with_fields[current_class])
+            )
+
+        if "# --- End of auto generated part. ---" in line:
+            current_line_is_part_of_autogenerated_code = False
+
+        if current_line_is_part_of_autogenerated_code:
+            continue
+
+        target_content_with_boilerplate.append(line)
+
+    for line_number, line in enumerate(target_content_with_boilerplate):
+        if not line.endswith("\n"):
+            target_content_with_boilerplate[line_number] += "\n"
+
+    with TARGET_FILE_PATH.open("w") as target_file:
+        target_file.writelines(target_content_with_boilerplate)
+
+
+def _generate_init(units: dict[str, str]) -> list[str]:
+    code = ["", " " * 4 + "def __init__(", " " * 8 + "self,"]
+
+    for unit in units:
+        code.append(" " * 8 + f"{unit}: float = 0.0,")
+
+    code.append(" " * 4 + ") -> None:")
+    code.append(" " * 8 + "self._base_value = 0.0")
+
+    for unit, factor in units.items():
+        code.append(" " * 8 + f"self._base_value += {unit} * {factor}")
+
+    code.append("")
+    return code
+
+
+def _generate_properties(current_class: str, units: dict[str, str]) -> list[str]:
+    code = []
+
+    for unit, factor in units.items():
+        code.append(" " * 4 + "@property")
+        code.append(" " * 4 + f"def {unit}(self) -> float:")
+        code.append(" " * 8 + f'"""The {current_class.lower()} in {unit.replace("_", " ")}."""')
+        code.append(" " * 8 + f"return self._base_value / {factor}")
+        code.append("")
+
+    return code
+
+
+if __name__ == "__main__":
+    quantities_with_fields = {
+        "Acceleration": {
+            "meters_per_square_second": "1",
+            "g_force": "(1 / 9.8)",
+        },
+        "Angle": {
+            "degrees": "(3.141592653589793 / 180)",
+            "radians": "1",
+        },
+        "Area": {
+            "square_miles": "1609.34**2",
+            "square_kilometers": "10 ** (3 * 2)",
+            "square_meters": "1",
+            "square_feet": "0.3048**2",
+            "square_inches": "0.0254**2",
+            "square_centimeters": "10 ** (-2 * 2)",
+            "square_millimeters": "10 ** (-3 * 2)",
+            "square_micrometers": "10 ** (-6 * 2)",
+        },
+        "Length": {
+            "miles": "1609.34",
+            "kilometers": "10**3",
+            "meters": "1",
+            "feet": "0.3048",
+            "inches": "0.0254",
+            "centimeters": "10**-2",
+            "millimeters": "10**-3",
+            "micrometers": "10**-6",
+        },
+        "Mass": {
+            "tonnes": "10**3",
+            "kilograms": "1",
+            "pounds": "(1 / 2.20462)",
+            "ounces": "(1 / 35.27396)",
+            "grams": "10**-3",
+            "milligrams": "10**-6",
+            "micrograms": "10**-9",
+        },
+        "Velocity": {
+            "meters_per_second": "1",
+            "kilometers_per_hour": "(1 / 3.6)",
+            "miles_per_hour": "(1 / 2.23694)",
+        },
+        "Time": {
+            "hours": "60 * 60",
+            "minutes": "60",
+            "seconds": "1",
+            "milliseconds": "10**-3",
+        },
+    }
+
+    generate_boilerplate(quantities_with_fields)
diff --git a/generate/quantities.py b/generate/quantities.py
new file mode 100644
index 0000000..43a9ab5
--- /dev/null
+++ b/generate/quantities.py
@@ -0,0 +1,27 @@
+from __future__ import annotations
+
+from ._quantity_base import _QuantityBase
+
+
+class Area(_QuantityBase):
+    """The two-dimensional extent of an object."""
+
+    # --- This part is auto generated. Do not change manually. ---
+
+    # --- End of auto generated part. ---
+
+
+class Length(_QuantityBase):
+    """The one-dimensional extent of an object or the distance between two points."""
+
+    # --- This part is auto generated. Do not change manually. ---
+
+    # --- End of auto generated part. ---
+
+
+class Time(_QuantityBase):
+    """The duration of an event."""
+
+    # --- This part is auto generated. Do not change manually. ---
+
+    # --- End of auto generated part. ---
diff --git a/pyproject.toml b/pyproject.toml
index 36996b5..45c74a9 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -20,7 +20,7 @@ pytest = "<9.0"
 line-length = 101
 
 [tool.ruff.lint]
-exclude = ["test/*"]
+exclude = ["test/*", "generate/*"]
 select = ["ALL"]
 ignore = [
     "COM812",  # conflicts with ruff formatter
@@ -32,6 +32,14 @@ ignore = [
 
     "ISC001",  # conflicts with ruff formatter
 
+    "N802",    # interferes with setting constant abstract properties
+
+    "PGH003",  # necessary for _QuantityBase.__eq__()
+
+    "PLR0913", # many arguments are necessary for the quantities to enable enough different units
+
+    "RUF012",  # does not work with constants
+
     "TCH001",  # adds hard to understand compexity without providing a benefit for smaller projects
     "TCH002",  # same as TCH001
     "TCH003",  # same as TCH001
diff --git a/quantio/__init__.py b/quantio/__init__.py
index 5419807..f73c24a 100644
--- a/quantio/__init__.py
+++ b/quantio/__init__.py
@@ -1,5 +1,6 @@
 """The main quantio package."""
 
-from .quantities import Length
+from .exceptions import CanNotAddTypesError, CanNotSubtractTypesError
+from .quantities import Length, Time
 
-__all__ = ["Length"]
+__all__ = ["Length", "Time", "CanNotAddTypesError", "CanNotSubtractTypesError"]
diff --git a/quantio/_quantity_base.py b/quantio/_quantity_base.py
new file mode 100644
index 0000000..f201f43
--- /dev/null
+++ b/quantio/_quantity_base.py
@@ -0,0 +1,37 @@
+from __future__ import annotations
+
+from abc import ABC
+
+from .exceptions import CanNotAddTypesError, CanNotSubtractTypesError
+
+
+class _QuantityBase(ABC):
+    """Parent class to all quantities."""
+
+    _base_value: float
+    "The base unit of the quantity."
+
+    def __eq__(self, other: object) -> bool:
+        """Assess if this object is the same as another."""
+        if isinstance(other, type(self)):
+            return self._base_value == other._base_value
+
+        return False
+
+    def __add__(self, other: _QuantityBase) -> _QuantityBase:
+        """Add two quantities of the same type."""
+        if type(self) is not type(other):
+            raise CanNotAddTypesError(self.__class__.__name__, other.__class__.__name__)
+
+        result = type(self)()
+        result._base_value = self._base_value + other._base_value
+        return result
+
+    def __sub__(self, other: _QuantityBase) -> _QuantityBase:
+        """Subtract two quantities of the same type."""
+        if type(self) is not type(other):
+            raise CanNotSubtractTypesError(self.__class__.__name__, other.__class__.__name__)
+
+        result = type(self)()
+        result._base_value = self._base_value - other._base_value
+        return result
diff --git a/quantio/exceptions.py b/quantio/exceptions.py
new file mode 100644
index 0000000..cae7dd4
--- /dev/null
+++ b/quantio/exceptions.py
@@ -0,0 +1,12 @@
+class CanNotAddTypesError(TypeError):
+    """Raised when two uncompatible quantities are added to one another."""
+
+    def __init__(self, self_type_descriptor: str, other_type_descriptor: str) -> None:
+        super().__init__(f"Can not add {other_type_descriptor} to {self_type_descriptor}")
+
+
+class CanNotSubtractTypesError(TypeError):
+    """Raised when two uncompatible quantities are subtracted from one another."""
+
+    def __init__(self, self_type_descriptor: str, other_type_descriptor: str) -> None:
+        super().__init__(f"Can not subtract {other_type_descriptor} from {self_type_descriptor}")
diff --git a/quantio/quantities.py b/quantio/quantities.py
index ed09fd0..916ca88 100644
--- a/quantio/quantities.py
+++ b/quantio/quantities.py
@@ -1,72 +1,332 @@
 from __future__ import annotations
 
-from typing import ClassVar
+from ._quantity_base import _QuantityBase
 
 
-class Length:
+class Acceleration(_QuantityBase):
+    """Rate of change of velocity."""
+
+    # --- This part is auto generated. Do not change manually. ---
+
+    def __init__(
+        self,
+        meters_per_square_second: float = 0.0,
+        g_force: float = 0.0,
+    ) -> None:
+        self._base_value = 0.0
+        self._base_value += meters_per_square_second * 1
+        self._base_value += g_force * (1 / 9.8)
+
+    @property
+    def meters_per_square_second(self) -> float:
+        """The acceleration in meters per square second."""
+        return self._base_value / 1
+
+    @property
+    def g_force(self) -> float:
+        """The acceleration in g force."""
+        return self._base_value / (1 / 9.8)
+
+    # --- End of auto generated part. ---
+
+
+class Angle(_QuantityBase):
+    """The figure formed by two rays."""
+
+    # --- This part is auto generated. Do not change manually. ---
+
+    def __init__(
+        self,
+        degrees: float = 0.0,
+        radians: float = 0.0,
+    ) -> None:
+        self._base_value = 0.0
+        self._base_value += degrees * (3.141592653589793 / 180)
+        self._base_value += radians * 1
+
+    @property
+    def degrees(self) -> float:
+        """The angle in degrees."""
+        return self._base_value / (3.141592653589793 / 180)
+
+    @property
+    def radians(self) -> float:
+        """The angle in radians."""
+        return self._base_value / 1
+
+    # --- End of auto generated part. ---
+
+
+class Area(_QuantityBase):
+    """The two-dimensional extent of an object."""
+
+    # --- This part is auto generated. Do not change manually. ---
+
+    def __init__(
+        self,
+        square_miles: float = 0.0,
+        square_kilometers: float = 0.0,
+        square_meters: float = 0.0,
+        square_feet: float = 0.0,
+        square_inches: float = 0.0,
+        square_centimeters: float = 0.0,
+        square_millimeters: float = 0.0,
+        square_micrometers: float = 0.0,
+    ) -> None:
+        self._base_value = 0.0
+        self._base_value += square_miles * 1609.34**2
+        self._base_value += square_kilometers * 10 ** (3 * 2)
+        self._base_value += square_meters * 1
+        self._base_value += square_feet * 0.3048**2
+        self._base_value += square_inches * 0.0254**2
+        self._base_value += square_centimeters * 10 ** (-2 * 2)
+        self._base_value += square_millimeters * 10 ** (-3 * 2)
+        self._base_value += square_micrometers * 10 ** (-6 * 2)
+
+    @property
+    def square_miles(self) -> float:
+        """The area in square miles."""
+        return self._base_value / 1609.34**2
+
+    @property
+    def square_kilometers(self) -> float:
+        """The area in square kilometers."""
+        return self._base_value / 10 ** (3 * 2)
+
+    @property
+    def square_meters(self) -> float:
+        """The area in square meters."""
+        return self._base_value / 1
+
+    @property
+    def square_feet(self) -> float:
+        """The area in square feet."""
+        return self._base_value / 0.3048**2
+
+    @property
+    def square_inches(self) -> float:
+        """The area in square inches."""
+        return self._base_value / 0.0254**2
+
+    @property
+    def square_centimeters(self) -> float:
+        """The area in square centimeters."""
+        return self._base_value / 10 ** (-2 * 2)
+
+    @property
+    def square_millimeters(self) -> float:
+        """The area in square millimeters."""
+        return self._base_value / 10 ** (-3 * 2)
+
+    @property
+    def square_micrometers(self) -> float:
+        """The area in square micrometers."""
+        return self._base_value / 10 ** (-6 * 2)
+
+    # --- End of auto generated part. ---
+
+
+class Length(_QuantityBase):
     """The one-dimensional extent of an object or the distance between two points."""
 
-    _meters: float
-    UNIT_CONVERSION: ClassVar[dict[str, float]] = {
-        "miles": 1609.34,
-        "kilometers": 10**3,
-        "meters": 10**0,
-        "feet": 0.3048,
-        "inches": 0.0254,
-        "centimeters": 10**-2,
-        "millimeters": 10**-3,
-        "micrometers": 10**-6,
-    }
-
-    def __init__(self, **kwargs: float) -> None:
-        """Construct this class with the used units."""
-        self._meters = (
-            kwargs.get("miles", 0.0) * self.UNIT_CONVERSION["miles"]
-            + kwargs.get("kilometers", 0.0) * self.UNIT_CONVERSION["kilometers"]
-            + kwargs.get("meters", 0.0) * self.UNIT_CONVERSION["meters"]
-            + kwargs.get("feet", 0.0) * self.UNIT_CONVERSION["feet"]
-            + kwargs.get("inches", 0.0) * self.UNIT_CONVERSION["inches"]
-            + kwargs.get("centimeters", 0.0) * self.UNIT_CONVERSION["centimeters"]
-            + kwargs.get("millimeters", 0.0) * self.UNIT_CONVERSION["millimeters"]
-            + kwargs.get("micrometers", 0.0) * self.UNIT_CONVERSION["micrometers"]
-        )
+    # --- This part is auto generated. Do not change manually. ---
+
+    def __init__(
+        self,
+        miles: float = 0.0,
+        kilometers: float = 0.0,
+        meters: float = 0.0,
+        feet: float = 0.0,
+        inches: float = 0.0,
+        centimeters: float = 0.0,
+        millimeters: float = 0.0,
+        micrometers: float = 0.0,
+    ) -> None:
+        self._base_value = 0.0
+        self._base_value += miles * 1609.34
+        self._base_value += kilometers * 10**3
+        self._base_value += meters * 1
+        self._base_value += feet * 0.3048
+        self._base_value += inches * 0.0254
+        self._base_value += centimeters * 10**-2
+        self._base_value += millimeters * 10**-3
+        self._base_value += micrometers * 10**-6
 
     @property
     def miles(self) -> float:
         """The length in miles."""
-        return self._meters / self.UNIT_CONVERSION["miles"]
+        return self._base_value / 1609.34
 
     @property
     def kilometers(self) -> float:
         """The length in kilometers."""
-        return self._meters / self.UNIT_CONVERSION["kilometers"]
+        return self._base_value / 10**3
 
     @property
     def meters(self) -> float:
         """The length in meters."""
-        return self._meters / self.UNIT_CONVERSION["meters"]
+        return self._base_value / 1
 
     @property
     def feet(self) -> float:
         """The length in feet."""
-        return self._meters / self.UNIT_CONVERSION["feet"]
+        return self._base_value / 0.3048
 
     @property
     def inches(self) -> float:
         """The length in inches."""
-        return self._meters / self.UNIT_CONVERSION["inches"]
+        return self._base_value / 0.0254
 
     @property
     def centimeters(self) -> float:
         """The length in centimeters."""
-        return self._meters / self.UNIT_CONVERSION["centimeters"]
+        return self._base_value / 10**-2
 
     @property
     def millimeters(self) -> float:
         """The length in millimeters."""
-        return self._meters / self.UNIT_CONVERSION["millimeters"]
+        return self._base_value / 10**-3
 
     @property
     def micrometers(self) -> float:
         """The length in micrometers."""
-        return self._meters / self.UNIT_CONVERSION["micrometers"]
+        return self._base_value / 10**-6
+
+    # --- End of auto generated part. ---
+
+
+class Mass(_QuantityBase):
+    """A measure of resistance to acceleration."""
+
+    # --- This part is auto generated. Do not change manually. ---
+
+    def __init__(
+        self,
+        tonnes: float = 0.0,
+        kilograms: float = 0.0,
+        pounds: float = 0.0,
+        ounces: float = 0.0,
+        grams: float = 0.0,
+        milligrams: float = 0.0,
+        micrograms: float = 0.0,
+    ) -> None:
+        self._base_value = 0.0
+        self._base_value += tonnes * 10**3
+        self._base_value += kilograms * 1
+        self._base_value += pounds * (1 / 2.20462)
+        self._base_value += ounces * (1 / 35.27396)
+        self._base_value += grams * 10**-3
+        self._base_value += milligrams * 10**-6
+        self._base_value += micrograms * 10**-9
+
+    @property
+    def tonnes(self) -> float:
+        """The mass in tonnes."""
+        return self._base_value / 10**3
+
+    @property
+    def kilograms(self) -> float:
+        """The mass in kilograms."""
+        return self._base_value / 1
+
+    @property
+    def pounds(self) -> float:
+        """The mass in pounds."""
+        return self._base_value / (1 / 2.20462)
+
+    @property
+    def ounces(self) -> float:
+        """The mass in ounces."""
+        return self._base_value / (1 / 35.27396)
+
+    @property
+    def grams(self) -> float:
+        """The mass in grams."""
+        return self._base_value / 10**-3
+
+    @property
+    def milligrams(self) -> float:
+        """The mass in milligrams."""
+        return self._base_value / 10**-6
+
+    @property
+    def micrograms(self) -> float:
+        """The mass in micrograms."""
+        return self._base_value / 10**-9
+
+    # --- End of auto generated part. ---
+
+
+class Velocity(_QuantityBase):
+    """Distance per time."""
+
+    # --- This part is auto generated. Do not change manually. ---
+
+    def __init__(
+        self,
+        meters_per_second: float = 0.0,
+        kilometers_per_hour: float = 0.0,
+        miles_per_hour: float = 0.0,
+    ) -> None:
+        self._base_value = 0.0
+        self._base_value += meters_per_second * 1
+        self._base_value += kilometers_per_hour * (1 / 3.6)
+        self._base_value += miles_per_hour * (1 / 2.23694)
+
+    @property
+    def meters_per_second(self) -> float:
+        """The velocity in meters per second."""
+        return self._base_value / 1
+
+    @property
+    def kilometers_per_hour(self) -> float:
+        """The velocity in kilometers per hour."""
+        return self._base_value / (1 / 3.6)
+
+    @property
+    def miles_per_hour(self) -> float:
+        """The velocity in miles per hour."""
+        return self._base_value / (1 / 2.23694)
+
+    # --- End of auto generated part. ---
+
+
+class Time(_QuantityBase):
+    """The duration of an event."""
+
+    # --- This part is auto generated. Do not change manually. ---
+
+    def __init__(
+        self,
+        hours: float = 0.0,
+        minutes: float = 0.0,
+        seconds: float = 0.0,
+        milliseconds: float = 0.0,
+    ) -> None:
+        self._base_value = 0.0
+        self._base_value += hours * 60 * 60
+        self._base_value += minutes * 60
+        self._base_value += seconds * 1
+        self._base_value += milliseconds * 10**-3
+
+    @property
+    def hours(self) -> float:
+        """The time in hours."""
+        return self._base_value / 60 * 60
+
+    @property
+    def minutes(self) -> float:
+        """The time in minutes."""
+        return self._base_value / 60
+
+    @property
+    def seconds(self) -> float:
+        """The time in seconds."""
+        return self._base_value / 1
+
+    @property
+    def milliseconds(self) -> float:
+        """The time in milliseconds."""
+        return self._base_value / 10**-3
+
+    # --- End of auto generated part. ---
diff --git a/test/test_length.py b/test/test_length.py
deleted file mode 100644
index 209af60..0000000
--- a/test/test_length.py
+++ /dev/null
@@ -1,52 +0,0 @@
-import pytest
-
-from quantio import Length
-
-
-def test_construction__multiple_units():
-    actual = Length(meters=5, kilometers=1, centimeters=7)
-    assert actual.meters == 1005.07
-
-
-def test_miles():
-    actual = Length(meters=1)
-    assert actual.miles == 1 / 1609.34
-
-
-def test_kilometers():
-    actual = Length(kilometers=1)
-    assert actual.kilometers == 1
-
-
-def test_meters():
-    actual = Length(meters=1)
-    assert actual.meters == 1
-
-
-def test_feet():
-    actual = Length(feet=1)
-    assert actual.feet == 1
-
-
-def test_inches():
-    actual = Length(inches=1)
-    assert actual.inches == 1
-
-
-def test_centimeters():
-    actual = Length(centimeters=1)
-    assert actual.centimeters == 1
-
-
-def test_millimeters():
-    actual = Length(millimeters=1)
-    assert actual.millimeters == 1
-
-
-def test_micrometers():
-    actual = Length(micrometers=1)
-    assert actual.micrometers == 1
-
-
-if __name__ == "__main__":
-    pytest.main([__file__, "-v"])
diff --git a/test/test_quantities_base.py b/test/test_quantities_base.py
new file mode 100644
index 0000000..05c4c67
--- /dev/null
+++ b/test/test_quantities_base.py
@@ -0,0 +1,42 @@
+import pytest
+
+from quantio import Length, CanNotAddTypesError, CanNotSubtractTypesError
+
+
+def test_construction__multiple_units():
+    actual = Length(meters=5, kilometers=1, centimeters=7)
+    assert actual.meters == 1005.07
+
+
+def test_add__success():
+    length1 = Length(meters=1)
+    length2 = Length(meters=2)
+
+    actual = length1 + length2
+    assert actual == Length(meters=3)
+
+
+def test_add__false_class():
+    length = Length(meters=1)
+
+    with pytest.raises(CanNotAddTypesError):
+        length += 1
+
+
+def test_sub__success():
+    length1 = Length(meters=1)
+    length2 = Length(meters=2)
+
+    actual = length2 - length1
+    assert actual == Length(meters=1)
+
+
+def test_sub__false_class():
+    length = Length(meters=1)
+
+    with pytest.raises(CanNotSubtractTypesError):
+        length -= 1
+
+
+if __name__ == "__main__":
+    pytest.main([__file__, "-v"])