diff --git a/public/js/components/Calendar/Mode/Day/View.js b/public/js/components/Calendar/Mode/Day/View.js
index 09738f1d0..cd953f33a 100644
--- a/public/js/components/Calendar/Mode/Day/View.js
+++ b/public/js/components/Calendar/Mode/Day/View.js
@@ -3,6 +3,8 @@ import LabelDay from '../../Base/Label/Day.js';
 import LabelDow from '../../Base/Label/Dow.js';
 import LabelTime from '../../Base/Label/Time.js';
 
+import { useResizeObserver } from '../../../../composables/Responsive.js';
+
 export default {
 	name: "DayView",
 	components: {
@@ -22,8 +24,7 @@ export default {
 			required: true
 		},
 		emptyMessage: String,
-		emptyMessageDetails: String,
-		compact: Boolean
+		emptyMessageDetails: String
 	},
 	emits: [
 		"requestModalOpen",
@@ -104,11 +105,21 @@ export default {
 			}
 		}
 	},
+	setup() {
+		const container = Vue.ref(null); // use useTemplateRef when updating to Vue 3.5
+		const { compact } = useResizeObserver(container, 750);
+
+		return {
+			container, // must be exposed or it won't be set in Vue < 3.5
+			compact
+		};
+	},
 	mounted() {
 		this.gridMainRef = this.$refs.grid.$refs.main;
 	},
 	template: /* html */`
 	<div
+		ref="container"
 		class="fhc-calendar-mode-day-view d-flex h-100"
 		@cal-click-default.capture="handleClickDefaults"
 	>
diff --git a/public/js/components/Cis/LvPlan/LvPlan.js b/public/js/components/Cis/LvPlan/LvPlan.js
index cdb2c38c1..4fbb7c871 100644
--- a/public/js/components/Cis/LvPlan/LvPlan.js
+++ b/public/js/components/Cis/LvPlan/LvPlan.js
@@ -34,8 +34,7 @@ export default {
 			modeOptions: {
 				day: {
 					emptyMessage: Vue.computed(() => this.$p.t('lehre/noLvFound')),
-					emptyMessageDetails: Vue.computed(() => this.$p.t('lehre/noLvFound')),
-					compact: false
+					emptyMessageDetails: Vue.computed(() => this.$p.t('lehre/noLvFound'))
 				},
 				week: {
 					collapseEmptyDays: false
diff --git a/public/js/components/Cis/Mylv/RoomInformation.js b/public/js/components/Cis/Mylv/RoomInformation.js
index ac02a9d51..0f4fa0603 100644
--- a/public/js/components/Cis/Mylv/RoomInformation.js
+++ b/public/js/components/Cis/Mylv/RoomInformation.js
@@ -32,8 +32,7 @@ export default {
 			modeOptions: {
 				day: {
 					emptyMessage: Vue.computed(() => this.$p.t('rauminfo/keineRaumReservierung')),
-					emptyMessageDetails: Vue.computed(() => this.$p.t('rauminfo/keineRaumReservierung')),
-					compact: false
+					emptyMessageDetails: Vue.computed(() => this.$p.t('rauminfo/keineRaumReservierung'))
 				},
 				week: {
 					collapseEmptyDays: false
diff --git a/public/js/composables/Responsive.js b/public/js/composables/Responsive.js
new file mode 100644
index 000000000..f1761d870
--- /dev/null
+++ b/public/js/composables/Responsive.js
@@ -0,0 +1,85 @@
+/**
+ * size returns the key of smallest threshold array (integer converts to
+ * { compact: threshold }) entry that is bigger than the current width of
+ * the element or 'full' if none is found.
+ * compact is true if the smallest threshold array entry is bigger than the
+ * current width or false otherwise.
+ *
+ * @param DOMElement|VueTemplateRef		element
+ * @param object|array|integer			threshold
+ * @return object						{ compact:Boolean, size:String }
+ */
+export function useResizeObserver(element, threshold) {
+	/* Result Vars */
+	const compact = Vue.ref(false);
+	const size = Vue.ref(false);
+
+	/* Helper Vars */
+	const mounted = Vue.ref(false);
+	const elementRef = Vue.computed(() => {
+		if (!Vue.isRef(element))
+			return element;
+		
+		if (!element.value)
+			return element.value;
+		
+		if (element.value.$el) // Maybe there is a better test
+			return element.value.$el;
+
+		return element.value;
+	});
+	const compareArray = Vue.computed(() => {
+		const input = Vue.isRef(threshold) ? threshold.value : threshold;
+		if (Number.isInteger(input))
+			return [['compact', input]];
+		if (Array.isArray(input))
+			return input.map((value, key) => [key, value]).sort((a, b) => a[1]-b[1]);
+		return Object.entries(input).sort((a, b) => a[1]-b[1]);
+	});
+
+	/* Helper Functions */
+	function updateResultVars() {
+		const compare = threshold.value || threshold;
+		if (elementRef.value.offsetWidth === undefined)
+			return;
+
+		const found = compareArray.value.find(compare => compare[1] > elementRef.value.offsetWidth);
+
+		size.value = found ? found[0] : 'full';
+		compact.value = (size.value == compareArray.value[0][0]);
+	}
+
+	/* Observer */
+	const observer = new ResizeObserver(() => {
+		if (elementRef.value) {
+			updateResultVars();
+		}
+	});
+	/* Observer Helper Functions */
+	function addObserver() {
+		if (!elementRef.value)
+			return;
+
+		updateResultVars();
+		observer.observe(elementRef.value);
+		mounted.value = true;
+	}
+	function removeObserver() {
+		if (mounted.value) {
+			observer.disconnect()
+		}
+	}
+
+	/* Main Logic */
+	Vue.onMounted(addObserver);
+	Vue.onUnmounted(removeObserver);
+	
+	Vue.watchEffect(() => {
+		if (elementRef.value) {
+			removeObserver();
+			addObserver();
+		}
+	});
+
+	return { compact, size };
+}
\ No newline at end of file