diff --git a/src/main/java/catering/inventory/InventoryController.java b/src/main/java/catering/inventory/InventoryController.java
index 27218f9..9eaabbc 100644
--- a/src/main/java/catering/inventory/InventoryController.java
+++ b/src/main/java/catering/inventory/InventoryController.java
@@ -33,6 +33,7 @@ import org.springframework.ui.Model;
 import org.springframework.util.Assert;
 import org.springframework.validation.Errors;
 import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.ModelAttribute;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.PostMapping;
 
@@ -85,9 +86,9 @@ class InventoryController {
 
 	@PreAuthorize("hasRole('ADMIN')")
 	@PostMapping("/inventory/edit/{pid}")
-	String edit(@Valid InventoryMutateForm form, Errors result, @PathVariable Product pid) {
+	String edit(@Valid @ModelAttribute("form") InventoryMutateForm form, Errors result, @PathVariable Product pid, Model model) {
 		if (result.hasErrors()) {
-			return "redirect:/inventory/edit/" + pid.getId();
+			return edit(model, pid, form);
 		}
 		CatalogDummy product = (CatalogDummy) pid;
 		UniqueInventoryItem item = inventory.findByProduct(pid).get();
@@ -109,17 +110,20 @@ class InventoryController {
 	@PreAuthorize("hasRole('ADMIN')")
 	@GetMapping("/inventory/add")
 	String add(Model model) {
-		model.addAttribute("actionIsAdd", true);
-		model.addAttribute("form", InventoryMutateForm.empty());
+		return add(model, InventoryMutateForm.empty());
+	}
 
+	String add(Model model, InventoryMutateForm form) {
+		model.addAttribute("actionIsAdd", true);
+		model.addAttribute("form", form);
 		return "inventory-mutate";
 	}
 
 	@PreAuthorize("hasRole('ADMIN')")
 	@PostMapping("/inventory/add")
-	String add(@Valid InventoryMutateForm form, Errors result) {
+	String add(@Valid @ModelAttribute("form") InventoryMutateForm form, Errors result, Model model) {
 		if (result.hasErrors()) {
-			return "inventory-mutate";
+			return add(model, form);
 		}
 		inventory.save(new UniqueInventoryItem(
 				cateringCatalog
diff --git a/src/main/resources/templates/inventory-mutate.html b/src/main/resources/templates/inventory-mutate.html
index 21efc93..3b2f612 100644
--- a/src/main/resources/templates/inventory-mutate.html
+++ b/src/main/resources/templates/inventory-mutate.html
@@ -10,30 +10,36 @@
 				<div class="mb-3">
 					<label class="form-label" for="type">Typ</label>
 					<div class="form-check form-check-inline" th:each="type : ${T(catering.catalog.CatalogDummyType).values()}">
-						<input class="form-check-input" type="radio" th:field="*{type}" th:value="${type}" th:text="${type}" required/>
+						<input class="form-check-input" type="radio" th:field="*{type}" th:value="${type}" th:text="${type}" th:errorclass="is-invalid" required/>
+						<div th:if="${#fields.hasErrors('type')}" class="invalid-feedback">Ungültiger Typ.</div>
 					</div>
 				</div>
 				<div class="mb-3">
 					<label class="form-label" for="name">Produktname</label>
-					<input class="form-control" type="text" th:field="*{name}" required/>
+					<input class="form-control" type="text" th:field="*{name}" th:errorclass="is-invalid" required/>
+					<div th:if="${#fields.hasErrors('name')}" class="invalid-feedback">Ungültiger Name.</div>
 				</div>
 				<div class="mb-3">
 					<label class="form-label" for="quantity">Menge im Bestand</label>
-					<input class="form-control" type="number" th:field="*{quantity}" required/>
+					<input class="form-control" type="number" th:field="*{quantity}" th:errorclass="is-invalid" required/>
+					<div th:if="${#fields.hasErrors('quantity')}" class="invalid-feedback">Ungültige Menge.</div>
 				</div>
 				<!-- the prices aren’t bound with th:field as they need special formatting -->
 				<div class="mb-3">
 					<label class="form-label" for="wholesalePrice">Einkaufspreis</label>
-					<input class="form-control" type="number" th:field="*{wholesalePrice}" step="0.01" min="0" required/>
+					<input class="form-control" type="number" name="wholesalePrice" th:value="${#numbers.formatDecimal(form.wholesalePrice, 1, 2)}" th:errorclass="is-invalid" step="0.01" min="0" required/>
+					<div th:if="${#fields.hasErrors('wholesalePrice')}" class="invalid-feedback">Ungültiger Einkaufspreis.</div>
 				</div>
 				<div class="mb-3">
 					<label class="form-label" for="retailPrice">UVP</label>
-					<input class="form-control" type="number" th:field="*{retailPrice}" step="0.01" min="0" required/>
+					<input class="form-control" type="number" name="retailPrice" th:value="${#numbers.formatDecimal(form.retailPrice, 1, 2)}" th:errorclass="is-invalid" step="0.01" min="0" required/>
+					<div th:if="${#fields.hasErrors('retailPrice')}" class="invalid-feedback">Ungültiger Verkaufspreis.</div>
 				</div>
 				<div class="mb-3">
 					<!-- FIXME darf nur bei angeboten als teil von partyservice angezeigt werden -->
 					<label class="form-label" for="promotionPrice">Aktionspreis</label>
-					<input class="form-control" type="number" th:field="*{promotionPrice}" step="0.01" min="0"/>
+					<input class="form-control" type="number" name="promotionPrice" th:value="${#numbers.formatDecimal(form.promotionPrice.orElse(null), 1, 2)}" th:errorclass="is-invalid" step="0.01" min="0"/>
+					<div th:if="${#fields.hasErrors('promotionPrice')}" class="invalid-feedback">Ungültiger Aktionspreis.</div>
 				</div>
 				<button class="btn btn-primary" type="submit" th:text="${actionIsAdd ? 'Hinzufügen' : 'Bearbeiten'}"></button>
 				<!-- KANN: Bild und Beschreibungstext -->