diff --git a/api/ovdashboard_api/dav_calendar.py b/api/ovdashboard_api/dav_calendar.py
index 8825918..b7f7d1d 100644
--- a/api/ovdashboard_api/dav_calendar.py
+++ b/api/ovdashboard_api/dav_calendar.py
@@ -12,7 +12,6 @@ from typing import Iterator
 
 from caldav import Calendar
 from caldav.lib.error import ReportError
-from isodate import parse_duration
 from pydantic import BaseModel, validator
 from vobject.base import Component
 
@@ -92,16 +91,14 @@ class CalEvent(BaseModel):
             except KeyError:
                 pass
 
+        print(data)
+
         if "dtend" not in data:
             data["dtend"] = data["dtstart"]
 
             if "duration" in data:
                 try:
-                    dtstart = datetime.fromisoformat(data["dtstart"])
-                    duration = parse_duration(data["duration"])
-                    dtend = dtstart + duration
-
-                    data["dtend"] = dtend.isoformat()
+                    data["dtend"] += data["duration"]
 
                 except (ValueError, TypeError, AttributeError):
                     _logger.warn(
@@ -110,7 +107,7 @@ class CalEvent(BaseModel):
                         repr(data["dtstart"]),
                     )
 
-                    data["dtend"] = data["dtstart"]
+                del data["duration"]
 
         return cls.parse_obj(data)
 
diff --git a/api/poetry.lock b/api/poetry.lock
index a72199f..7f35829 100644
--- a/api/poetry.lock
+++ b/api/poetry.lock
@@ -127,17 +127,6 @@ docs = ["jaraco.packaging (>=9)", "rst.linker (>=1.9)", "sphinx"]
 perf = ["ipython"]
 testing = ["flufl.flake8", "importlib-resources (>=1.3)", "packaging", "pyfakefs", "pytest (>=6)", "pytest-black (>=0.3.7)", "pytest-checkdocs (>=2.4)", "pytest-cov", "pytest-enabler (>=1.3)", "pytest-flake8", "pytest-mypy (>=0.9.1)", "pytest-perf (>=0.9.2)"]
 
-[[package]]
-name = "isodate"
-version = "0.6.1"
-description = "An ISO 8601 date/time/duration parser and formatter"
-category = "main"
-optional = false
-python-versions = "*"
-
-[package.dependencies]
-six = "*"
-
 [[package]]
 name = "lxml"
 version = "4.9.1"
@@ -407,7 +396,7 @@ testing = ["func-timeout", "jaraco.itertools", "pytest (>=6)", "pytest-black (>=
 [metadata]
 lock-version = "1.1"
 python-versions = "^3.9"
-content-hash = "6fb83bae86629a411b61f4964ac137fdaec272a89d6b02db6938269a8d1eef91"
+content-hash = "b25d37c0bf9187d599709a66e05d21c0df7da2b140373f6cd50b070ae2f073ab"
 
 [metadata.files]
 anyio = [
@@ -454,10 +443,6 @@ importlib-metadata = [
     {file = "importlib_metadata-4.12.0-py3-none-any.whl", hash = "sha256:7401a975809ea1fdc658c3aa4f78cc2195a0e019c5cbc4c06122884e9ae80c23"},
     {file = "importlib_metadata-4.12.0.tar.gz", hash = "sha256:637245b8bab2b6502fcbc752cc4b7a6f6243bb02b31c5c26156ad103d3d45670"},
 ]
-isodate = [
-    {file = "isodate-0.6.1-py2.py3-none-any.whl", hash = "sha256:0751eece944162659049d35f4f549ed815792b38793f07cf73381c1c87cbed96"},
-    {file = "isodate-0.6.1.tar.gz", hash = "sha256:48c5881de7e8b0a0d648cb024c8062dc84e7b840ed81e864c7614fd3c127bde9"},
-]
 lxml = [
     {file = "lxml-4.9.1-cp27-cp27m-macosx_10_15_x86_64.whl", hash = "sha256:98cafc618614d72b02185ac583c6f7796202062c41d2eeecdf07820bad3295ed"},
     {file = "lxml-4.9.1-cp27-cp27m-manylinux_2_5_i686.manylinux1_i686.whl", hash = "sha256:c62e8dd9754b7debda0c5ba59d34509c4688f853588d75b53c3791983faa96fc"},
diff --git a/api/pyproject.toml b/api/pyproject.toml
index cc2a6c3..7d73f01 100644
--- a/api/pyproject.toml
+++ b/api/pyproject.toml
@@ -18,7 +18,6 @@ tomli = "^2.0.1"
 tomli-w = "^1.0.0"
 uvicorn = "^0.18.3"
 webdavclient3 = "3.14.5"
-isodate = "^0.6.1"
 
 [tool.poetry.dev-dependencies]
 # pytest = "^5.2"