diff --git a/src/allotment.tsx b/src/allotment.tsx
index 5b82b266..afc5d9ef 100644
--- a/src/allotment.tsx
+++ b/src/allotment.tsx
@@ -91,6 +91,7 @@ Pane.displayName = "Allotment.Pane";
 export type AllotmentHandle = {
   reset: () => void;
   resize: (sizes: number[]) => void;
+  getContainerSize: () => { width: number; height: number };
 };
 
 export type AllotmentProps = {
@@ -140,7 +141,7 @@ const Allotment = forwardRef<AllotmentHandle, AllotmentProps>(
       onReset,
       onVisibleChange,
       onDragStart,
-      onDragEnd
+      onDragEnd,
     },
     ref
   ) => {
@@ -150,6 +151,10 @@ const Allotment = forwardRef<AllotmentHandle, AllotmentProps>(
     const splitViewRef = useRef<SplitView | null>(null);
     const splitViewViewRef = useRef(new Map<React.Key, HTMLElement>());
     const layoutService = useRef<LayoutService>(new LayoutService());
+    const containerSizeRef = useRef<{ width: number; height: number }>({
+      height: 0,
+      width: 0,
+    });
     const views = useRef<PaneView[]>([]);
 
     const [dimensionsInitialized, setDimensionsInitialized] = useState(false);
@@ -192,6 +197,7 @@ const Allotment = forwardRef<AllotmentHandle, AllotmentProps>(
       resize: (sizes) => {
         splitViewRef.current?.resizeViews(sizes);
       },
+      getContainerSize: () => ({ ...containerSizeRef.current }),
     }));
 
     useIsomorphicLayoutEffect(() => {
@@ -219,34 +225,34 @@ const Allotment = forwardRef<AllotmentHandle, AllotmentProps>(
         proportionalLayout,
         ...(initializeSizes &&
           defaultSizes && {
-          descriptor: {
-            size: defaultSizes.reduce((a, b) => a + b, 0),
-            views: defaultSizes.map((size, index) => {
-              const props = splitViewPropsRef.current.get(
-                previousKeys.current[index]
-              );
-
-              const view = new PaneView(layoutService.current, {
-                element: document.createElement("div"),
-                minimumSize: props?.minSize ?? minSize,
-                maximumSize: props?.maxSize ?? maxSize,
-                priority: props?.priority ?? LayoutPriority.Normal,
-                ...(props?.preferredSize && {
-                  preferredSize: props?.preferredSize,
-                }),
-                snap: props?.snap ?? snap,
-              });
-
-              views.current.push(view);
+            descriptor: {
+              size: defaultSizes.reduce((a, b) => a + b, 0),
+              views: defaultSizes.map((size, index) => {
+                const props = splitViewPropsRef.current.get(
+                  previousKeys.current[index]
+                );
 
-              return {
-                container: [...splitViewViewRef.current.values()][index],
-                size: size,
-                view: view,
-              };
-            }),
-          },
-        }),
+                const view = new PaneView(layoutService.current, {
+                  element: document.createElement("div"),
+                  minimumSize: props?.minSize ?? minSize,
+                  maximumSize: props?.maxSize ?? maxSize,
+                  priority: props?.priority ?? LayoutPriority.Normal,
+                  ...(props?.preferredSize && {
+                    preferredSize: props?.preferredSize,
+                  }),
+                  snap: props?.snap ?? snap,
+                });
+
+                views.current.push(view);
+
+                return {
+                  container: [...splitViewViewRef.current.values()][index],
+                  size: size,
+                  view: view,
+                };
+              }),
+            },
+          }),
       };
 
       splitViewRef.current = new SplitView(
@@ -254,8 +260,7 @@ const Allotment = forwardRef<AllotmentHandle, AllotmentProps>(
         options,
         onChange,
         onDragStart,
-        onDragEnd,
-        
+        onDragEnd
       );
 
       splitViewRef.current.on("sashDragStart", () => {
@@ -472,6 +477,8 @@ const Allotment = forwardRef<AllotmentHandle, AllotmentProps>(
       ref: containerRef,
       onResize: ({ width, height }) => {
         if (width && height) {
+          containerSizeRef.current.height = height;
+          containerSizeRef.current.width = width;
           splitViewRef.current?.layout(vertical ? height : width);
           layoutService.current.setSize(vertical ? height : width);
           setDimensionsInitialized(true);