diff --git a/src/Playroom/Playroom.tsx b/src/Playroom/Playroom.tsx
index daab827d..69062f0b 100644
--- a/src/Playroom/Playroom.tsx
+++ b/src/Playroom/Playroom.tsx
@@ -133,18 +133,11 @@ export default ({ components, themes, widths, snippets }: PlayroomProps) => {
     </Fragment>
   );
 
-  if (editorHeightPercentage < 0 || editorHeightPercentage > 100) {
-    throw new Error('editorHeightPercentage must be a value between 0 and 100');
-  }
-  if (editorWidthPercentage < 0 || editorWidthPercentage > 100) {
-    throw new Error('editorWidthPercentage must be a value between 0 and 100');
-  }
-
   const isVerticalEditor = editorPosition === 'right';
   const isHorizontalEditor = editorPosition === 'bottom';
   const sizeStyles = {
-    height: isHorizontalEditor ? `${editorHeightPercentage}%` : 'auto', // issue in ff & safari when not a string
-    width: isVerticalEditor ? `${editorWidthPercentage}%` : 'auto',
+    height: isHorizontalEditor ? editorHeightPercentage : 'auto', // issue in ff & safari when not a string
+    width: isVerticalEditor ? editorWidthPercentage : 'auto',
   };
   const editorContainer =
     editorPosition === 'undocked' ? (
@@ -189,8 +182,8 @@ export default ({ components, themes, widths, snippets }: PlayroomProps) => {
           editorHidden
             ? undefined
             : {
-                right: { right: `${editorWidthPercentage}%` },
-                bottom: { bottom: `${editorHeightPercentage}%` },
+                right: { right: editorWidthPercentage },
+                bottom: { bottom: editorHeightPercentage },
                 undocked: undefined,
               }[editorPosition]
         }
diff --git a/src/StoreContext/StoreContext.tsx b/src/StoreContext/StoreContext.tsx
index eee70e5a..11a34122 100644
--- a/src/StoreContext/StoreContext.tsx
+++ b/src/StoreContext/StoreContext.tsx
@@ -65,8 +65,8 @@ interface State {
   cursorPosition: CursorPosition;
   editorHidden: boolean;
   editorPosition: EditorPosition;
-  editorHeightPercentage: number;
-  editorWidthPercentage: number;
+  editorHeightPercentage: string;
+  editorWidthPercentage: string;
   statusMessage?: StatusMessage;
   visibleThemes?: string[];
   visibleWidths?: number[];
@@ -329,7 +329,10 @@ const createReducer =
       case 'updateEditorHeight': {
         const { size } = action.payload;
         const viewportHeight = window.innerHeight;
-        const heightPercentage = (size / viewportHeight) * 100;
+        const heightPercentage = `${Math.round(
+          (size / viewportHeight) * 100
+        )}%`;
+
         store.setItem('editorHeightPercentage', heightPercentage);
 
         return {
@@ -341,7 +344,7 @@ const createReducer =
       case 'updateEditorWidth': {
         const { size } = action.payload;
         const viewportWidth = window.innerWidth;
-        const widthPercentage = (size / viewportWidth) * 100;
+        const widthPercentage = `${Math.round((size / viewportWidth) * 100)}%`;
         store.setItem('editorWidthPercentage', widthPercentage);
 
         return {
@@ -412,8 +415,8 @@ const initialState: State = {
   cursorPosition: { line: 0, ch: 0 },
   editorHidden: false,
   editorPosition: defaultPosition,
-  editorHeightPercentage: 40,
-  editorWidthPercentage: 40,
+  editorHeightPercentage: '40%',
+  editorWidthPercentage: '40%',
   ready: false,
   colorScheme: 'light',
 };
@@ -477,8 +480,8 @@ export const StoreProvider = ({
     Promise.all([
       store.getItem<string>('code'),
       store.getItem<EditorPosition>('editorPosition'),
-      store.getItem<number>('editorHeightPercentage'),
-      store.getItem<number>('editorWidthPercentage'),
+      store.getItem<string>('editorHeightPercentage'),
+      store.getItem<string>('editorWidthPercentage'),
       store.getItem<number[]>('visibleWidths'),
       store.getItem<string[]>('visibleThemes'),
       store.getItem<ColorScheme>('colorScheme'),
@@ -512,8 +515,10 @@ export const StoreProvider = ({
           payload: {
             ...(code ? { code } : {}),
             ...(editorPosition ? { editorPosition } : {}),
-            ...(editorHeightPercentage ? { editorHeightPercentage } : {}),
-            ...(editorWidthPercentage ? { editorWidthPercentage } : {}),
+            ...(editorHeightPercentage
+              ? { editorHeightPercentage }
+              : undefined),
+            ...(editorWidthPercentage ? { editorWidthPercentage } : undefined),
             ...(visibleThemes ? { visibleThemes } : {}),
             ...(visibleWidths ? { visibleWidths } : {}),
             ...(colorScheme ? { colorScheme } : {}),