diff --git a/frontend/src/components/AddSpendingModal.vue b/frontend/src/components/AddSpendingModal.vue
new file mode 100644
index 0000000..ad5bbe7
--- /dev/null
+++ b/frontend/src/components/AddSpendingModal.vue
@@ -0,0 +1,84 @@
+<script setup lang="ts">
+import IconPlus from '@/components/icons/IconPlusCircle.vue'
+import IconX from '@/components/icons/IconX.vue'
+import { useBoardStore } from '@/stores/boardStore'
+
+import { computed, ref } from 'vue'
+import InputField from './InputField.vue'
+
+const props = defineProps({
+  userName: String,
+})
+
+const store = useBoardStore()
+const isOpen = ref(false)
+const spendingNameInput = ref('')
+const spendingNameError = computed(() => {
+  if (spendingNameInput.value.trim().length == 0) return 'Required'
+  return ''
+})
+const spendingAmountInput = ref('')
+const spendingAmount = computed(() => {
+  return Number(parseFloat(spendingAmountInput.value.trim().replace('€', '')).toFixed(2))
+})
+const spendingAmountError = computed(() => {
+  if (spendingAmountInput.value.trim().length == 0) return 'Required'
+  if (isNaN(spendingAmount.value)) return 'Invalid'
+  return ''
+})
+const forceValidate = ref(false)
+
+function submit() {
+  forceValidate.value = true
+  if (spendingAmountError.value == '' && spendingNameError.value == '') {
+    store
+      .getCurrentBoard()
+      .addSpendingByUserName(
+        props.userName ?? '',
+        spendingNameInput.value,
+        spendingAmount.value * 100,
+      )
+    spendingNameInput.value = ''
+    spendingAmountInput.value = ''
+    isOpen.value = false
+  }
+}
+</script>
+
+<template>
+  <button class="btn btn-square btn-ghost" @click="isOpen = true">
+    <IconPlus />
+  </button>
+  <dialog class="modal" :class="{ 'modal-open': isOpen }">
+    <div class="modal-box fieldset p-4">
+      <form method="dialog" @submit.prevent="submit">
+        <button
+          class="btn btn-sm btn-circle btn-ghost absolute right-2 top-2"
+          @click="isOpen = false"
+        >
+          <IconX></IconX>
+        </button>
+
+        <div class="flex flex-col gap-2">
+          <h3 class="text-lg font-bold">Hinzufügen von Ausgabe für {{ props.userName }}</h3>
+
+          <InputField
+            label="Bezeichnung"
+            v-model:input-text="spendingNameInput"
+            :input-error="spendingNameError"
+            :force-validate="forceValidate"
+          ></InputField>
+          <InputField
+            label="Betrag"
+            v-model:input-text="spendingAmountInput"
+            :input-error="spendingAmountError"
+            :force-validate="forceValidate"
+            placeholder="0,00€"
+          ></InputField>
+
+          <button class="btn btn-neutral mt-5" type="submit">Hinzufügen</button>
+        </div>
+      </form>
+    </div>
+  </dialog>
+</template>
diff --git a/frontend/src/components/CreateNewList.vue b/frontend/src/components/CreateNewList.vue
index ffca4ed..0354dbe 100644
--- a/frontend/src/components/CreateNewList.vue
+++ b/frontend/src/components/CreateNewList.vue
@@ -1,11 +1,42 @@
-<script setup lang="ts"></script>
+<script setup lang="ts">
+import InputField from './InputField.vue'
+import { useBoardStore } from '@/stores/boardStore'
+import { computed, ref } from 'vue'
+import { useRouter } from 'vue-router'
+
+const route = useRouter()
+const store = useBoardStore()
+
+const boardNameInput = ref('')
+const boardNameError = computed(() => {
+  if (boardNameInput.value.trim().length == 0) return 'Required'
+  return ''
+})
+const forceValidate = ref(false)
+
+function submit() {
+  forceValidate.value = true
+  if (boardNameError.value == '') {
+    const newBoard = store.createBoard(boardNameInput.value)
+    route.push('/boards/' + newBoard.guid)
+  }
+}
+</script>
 
 <template>
-  <fieldset class="fieldset bg-base-200 border-base-300 rounded-box w-xs border p-4">
-    <legend class="fieldset-legend">Neue Liste Erstellen</legend>
-    <div class="join">
-      <input type="text" class="input join-item" placeholder="Listenname" />
-      <button class="btn join-item">Erstellen</button>
+  <form class="bg-base-200 border-base-300 rounded-box w-xs border p-4" @submit.prevent="submit">
+    <div class="flex flex-col gap-2">
+      <h3 class="font-bold">Neue Liste Erstellen</h3>
+
+      <InputField
+        label=""
+        placeholder="Listenname"
+        v-model:input-text="boardNameInput"
+        :input-error="boardNameError"
+        :force-validate="forceValidate"
+      ></InputField>
+
+      <button class="btn btn-neutral mt-5" type="submit">Erstellen</button>
     </div>
-  </fieldset>
+  </form>
 </template>
diff --git a/frontend/src/components/InputField.vue b/frontend/src/components/InputField.vue
new file mode 100644
index 0000000..59edb65
--- /dev/null
+++ b/frontend/src/components/InputField.vue
@@ -0,0 +1,32 @@
+<script setup lang="ts">
+import { ref } from 'vue'
+
+const props = defineProps({
+  label: String,
+  placeholder: String,
+  inputError: String,
+  forceValidate: Boolean,
+})
+const inputText = defineModel('inputText')
+
+const touched = ref(false)
+</script>
+
+<template>
+  <label class="label">{{ props.label }}</label>
+  <input
+    :class="[
+      'input w-full',
+      { 'input-error': (touched || props.forceValidate) && props.inputError !== '' },
+    ]"
+    :placeholder="props.placeholder"
+    v-model="inputText"
+    @blur="touched = true"
+  />
+  <div
+    v-if="(touched || props.forceValidate) && props.inputError !== ''"
+    class="text-error text-sm mt-1"
+  >
+    {{ props.inputError }}
+  </div>
+</template>
diff --git a/frontend/src/components/icons/IconX.vue b/frontend/src/components/icons/IconX.vue
new file mode 100644
index 0000000..59d156a
--- /dev/null
+++ b/frontend/src/components/icons/IconX.vue
@@ -0,0 +1,12 @@
+<template>
+  <svg
+    xmlns="http://www.w3.org/2000/svg"
+    fill="none"
+    viewBox="0 0 24 24"
+    stroke-width="1.5"
+    stroke="currentColor"
+    class="size-4"
+  >
+    <path stroke-linecap="round" stroke-linejoin="round" d="M6 18 18 6M6 6l12 12" />
+  </svg>
+</template>
diff --git a/frontend/src/services/Board.ts b/frontend/src/services/Board.ts
index 5f2fbb9..4e48b99 100644
--- a/frontend/src/services/Board.ts
+++ b/frontend/src/services/Board.ts
@@ -1,3 +1,4 @@
+import { Spending } from './Spending'
 import { User } from './User'
 import { v4 as uuidv4 } from 'uuid'
 
@@ -17,4 +18,9 @@ export class Board {
   addUser(user: User): void {
     this.users.push(user)
   }
+
+  addSpendingByUserName(userName: string, spendingName: string, amountCt: number) {
+    const user = this.users.filter((u) => u.name === userName)[0]
+    user?.addSpending(new Spending(spendingName, amountCt))
+  }
 }
diff --git a/frontend/src/stores/boardStore.ts b/frontend/src/stores/boardStore.ts
index 56b3d42..4128958 100644
--- a/frontend/src/stores/boardStore.ts
+++ b/frontend/src/stores/boardStore.ts
@@ -7,6 +7,7 @@ import { Spending } from '@/services/Spending'
 export const useBoardStore = defineStore('boardStore', () => {
   const route = useRoute()
   const boards = new Map<string, Board>()
+  let testBoard: Board | undefined
 
   function createBoard(name: string): Board {
     const newBoard = new Board(name)
@@ -19,15 +20,18 @@ export const useBoardStore = defineStore('boardStore', () => {
     if (board != undefined) {
       return board
     } else {
-      const testBoard = new Board('Grill and Chill')
-      const elias = new User('Elias')
-      elias.addSpending(new Spending('Burger', 1230))
-      elias.addSpending(new Spending('Kaffee', 510))
-      testBoard.addUser(elias)
-      const max = new User('Max')
-      max.addSpending(new Spending('Omlett', 1822))
-      max.addSpending(new Spending('Kaffee', 3073))
-      testBoard.addUser(max)
+      if (testBoard === undefined) {
+        testBoard = new Board('Grill and Chill')
+        const elias = new User('Elias')
+        elias.addSpending(new Spending('Burger', 1230))
+        elias.addSpending(new Spending('Kaffee', 510))
+        testBoard.addUser(elias)
+        const max = new User('Max')
+        max.addSpending(new Spending('Omlett', 1822))
+        max.addSpending(new Spending('Kaffee', 3073))
+        testBoard.addUser(max)
+        return testBoard
+      }
       return testBoard
     }
   }
diff --git a/frontend/src/views/BoardUsersView.vue b/frontend/src/views/BoardUsersView.vue
index 65b7b3a..e980001 100644
--- a/frontend/src/views/BoardUsersView.vue
+++ b/frontend/src/views/BoardUsersView.vue
@@ -1,7 +1,7 @@
 <script setup lang="ts">
+import AddSpendingModal from '@/components/AddSpendingModal.vue'
 import ItemList from '@/components/ItemList.vue'
 import ItemListElement from '@/components/ItemListElement.vue'
-import IconPlus from '@/components/icons/IconPlusCircle.vue'
 
 import { useBoardStore } from '@/stores/boardStore'
 import { ref } from 'vue'
@@ -20,9 +20,7 @@ const users = ref(store.getCurrentBoard().users)
       :subtitle="(user.getTotalSpending() / 100).toFixed(2) + '€'"
       subtitle-class="text-green-700"
     >
-      <button class="btn btn-square btn-ghost">
-        <IconPlus />
-      </button>
+      <AddSpendingModal :user-name="user.name"></AddSpendingModal>
     </ItemListElement>
   </ItemList>
 </template>