diff --git a/apps/contests/models.py b/apps/contests/models.py
index c5e8e71..52fceeb 100644
--- a/apps/contests/models.py
+++ b/apps/contests/models.py
@@ -1,6 +1,5 @@
 from typing import Any
 
-from django import forms
 from django.core.exceptions import ValidationError
 from django.db.models import (
     BooleanField,
@@ -8,7 +7,6 @@
     DateTimeField,
     ManyToManyField,
 )
-from django.utils import timezone
 from django.utils.timezone import now
 
 from apps.contests.enums import ContestStatus
@@ -48,22 +46,8 @@ def status(self) -> ContestStatus:
         else:
             return ContestStatus.RUNNING
 
+    def clean(self) -> Any:
+        super().clean()
 
-class ContestAdminForm(forms.ModelForm["Contest"]):
-    def clean_start_time(self) -> Any:
-        start_time = self.cleaned_data.get("start_time")
-        if start_time and start_time <= timezone.now():
-            raise ValidationError("A data de início deve estar no futuro.")
-
-        return start_time
-
-    def clean_end_time(self) -> Any:
-        end_time = self.cleaned_data.get("end_time")
-        start_time = self.cleaned_data.get("start_time")
-
-        if end_time and end_time <= start_time:
-            raise ValidationError(
-                "A data de término deve ser posterior a data de início."
-            )
-
-        return end_time
+        if self.start_time > self.end_time:
+            raise ValidationError("Start time must be before end time.")