diff --git a/studio/frontend/src/features/studio/sections/dataset-section.tsx b/studio/frontend/src/features/studio/sections/dataset-section.tsx
index 7ff9e675ab..4f20133b5c 100644
--- a/studio/frontend/src/features/studio/sections/dataset-section.tsx
+++ b/studio/frontend/src/features/studio/sections/dataset-section.tsx
@@ -89,6 +89,13 @@ function formatUpdatedDate(timestamp: number | null): string {
   return new Date(timestamp * 1000).toLocaleDateString();
 }
 
+function normalizeSliceInput(value: string): string | null {
+  const trimmed = value.trim();
+  if (!trimmed) return null;
+  if (!/^\d+$/.test(trimmed)) return null;
+  return trimmed;
+}
+
 export function DatasetSection() {
   const {
     dataset,
@@ -783,11 +790,14 @@ export function DatasetSection() {
                       </Tooltip>
                     </span>
                     <Input
+                      type="number"
                       inputMode="numeric"
+                      min={0}
+                      step={1}
                       placeholder="0"
                       value={datasetSliceStart ?? ""}
                       onChange={(e) =>
-                        setDatasetSliceStart(e.target.value || null)
+                        setDatasetSliceStart(normalizeSliceInput(e.target.value))
                       }
                     />
                   </div>
@@ -815,11 +825,14 @@ export function DatasetSection() {
                       </Tooltip>
                     </span>
                     <Input
+                      type="number"
                       inputMode="numeric"
+                      min={0}
+                      step={1}
                       placeholder="End"
                       value={datasetSliceEnd ?? ""}
                       onChange={(e) =>
-                        setDatasetSliceEnd(e.target.value || null)
+                        setDatasetSliceEnd(normalizeSliceInput(e.target.value))
                       }
                     />
                   </div>
diff --git a/studio/frontend/src/features/training/api/mappers.ts b/studio/frontend/src/features/training/api/mappers.ts
index fed17a538c..53869fdd59 100644
--- a/studio/frontend/src/features/training/api/mappers.ts
+++ b/studio/frontend/src/features/training/api/mappers.ts
@@ -12,7 +12,7 @@ function parseSliceValue(value: string | null): number | null {
   const trimmed = value.trim();
   if (!trimmed) return null;
   const num = Number(trimmed);
-  if (!Number.isFinite(num) || !Number.isInteger(num)) return null;
+  if (!Number.isFinite(num) || !Number.isInteger(num) || num < 0) return null;
   return num;
 }