diff --git a/api/components/IsoDateInput.vue b/api/components/IsoDateInput.vue
index 48ed355..ac873e0 100644
--- a/api/components/IsoDateInput.vue
+++ b/api/components/IsoDateInput.vue
@@ -54,7 +54,7 @@ export default defineComponent({
     label: { type: String, default: 'Datum' },
     readonly: Boolean,
     rules: {
-      type: Array as PropType<Validator[]>,
+      type: Array as PropType<Validator<Date>[]>,
       default: () => [],
     },
   },
@@ -62,7 +62,21 @@ export default defineComponent({
   setup(props, { emit, attrs }) {
     const customRules = computed(() => [
       props.type == 'date' ? stringIsDate : props.type == 'time' ? stringIsTime : stringIsDateTime,
-      ...props.rules,
+      (value?: string | null) => {
+        if (props.rules.length > 0 && value) {
+          let date: Date | undefined = undefined;
+          if (props.type == 'date') date = modifyDate(value);
+          else if (props.type == 'time') date = modifyTime(value);
+          else {
+            const split = value.split(' ');
+            date = modifyTime(split[1], modifyDate(split[0]));
+          }
+          props.rules.forEach((rule) => {
+            const r = rule(date);
+            if (typeof r === 'string') return r;
+          });
+        }
+      },
     ]);
 
     const clearable = computed(() =>
diff --git a/api/src/utils/validators.ts b/api/src/utils/validators.ts
index e77a436..2db8e8c 100644
--- a/api/src/utils/validators.ts
+++ b/api/src/utils/validators.ts
@@ -1,4 +1,4 @@
-export type Validator = (value: unknown) => boolean | string;
+export type Validator<T = unknown> = (value?: T | null) => boolean | string;
 
 export function notEmpty(val: unknown) {
   return !!val || 'Feld darf nicht leer sein!';