diff --git a/src/ol/Map.js b/src/ol/Map.js
index d0cae90c372..70c2c47be1d 100644
--- a/src/ol/Map.js
+++ b/src/ol/Map.js
@@ -1367,7 +1367,7 @@ class Map extends BaseObject {
     }
     const view = this.getView();
     if (view) {
-      this.updateViewportSize_();
+      this.updateViewportSize_(this.getSize());
 
       this.viewPropertyListenerKey_ = listen(
         view,
@@ -1738,25 +1738,18 @@ class Map extends BaseObject {
     const oldSize = this.getSize();
     if (size && (!oldSize || !equals(size, oldSize))) {
       this.setSize(size);
-      this.updateViewportSize_();
+      this.updateViewportSize_(size);
     }
   }
 
   /**
    * Recomputes the viewport size and save it on the view object (if any)
+   * @param {import("./size.js").Size|undefined} size The size.
    * @private
    */
-  updateViewportSize_() {
+  updateViewportSize_(size) {
     const view = this.getView();
     if (view) {
-      let size = undefined;
-      const computedStyle = getComputedStyle(this.viewport_);
-      if (computedStyle.width && computedStyle.height) {
-        size = [
-          parseInt(computedStyle.width, 10),
-          parseInt(computedStyle.height, 10),
-        ];
-      }
       view.setViewportSize(size);
     }
   }
diff --git a/src/ol/View.js b/src/ol/View.js
index 07cc0d28709..39ec72b70f4 100644
--- a/src/ol/View.js
+++ b/src/ol/View.js
@@ -74,9 +74,10 @@ import {fromExtent as polygonFromExtent} from './geom/Polygon.js';
 
 /**
  * @typedef {Object} FitOptions
- * @property {import("./size.js").Size} [size] The size in pixels of the box to fit
- * the extent into. Default is the current size of the first map in the DOM that
- * uses this view, or `[100, 100]` if no such map is found.
+ * @property {import("./size.js").Size} [size] The size in pixels of the box to
+ * fit the extent into. Defaults to the size of the map the view is associated with.
+ * If no map or multiple maps are connected to the view, provide the desired box size
+ * (e.g. `map.getSize()`).
  * @property {!Array<number>} [padding=[0, 0, 0, 0]] Padding (in pixels) to be
  * cleared inside the view. Values in the array are top, right, bottom and left
  * padding.
@@ -986,12 +987,12 @@ class View extends BaseObject {
   }
 
   /**
-   * Calculate the extent for the current view state and the passed size.
-   * The size is the pixel dimensions of the box into which the calculated extent
-   * should fit. In most cases you want to get the extent of the entire map,
-   * that is `map.getSize()`.
-   * @param {import("./size.js").Size} [size] Box pixel size. If not provided, the size
-   * of the map that uses this view will be used.
+   * Calculate the extent for the current view state and the passed box size.
+   * @param {import("./size.js").Size} [size] The pixel dimensions of the box
+   * into which the calculated extent should fit. Defaults to the size of the
+   * map the view is associated with.
+   * If no map or multiple maps are connected to the view, provide the desired
+   * box size (e.g. `map.getSize()`).
    * @return {import("./extent.js").Extent} Extent.
    * @api
    */