diff --git a/src/ol/PluggableMap.js b/src/ol/PluggableMap.js
index 97ecd273ec..f8ceb3310d 100644
--- a/src/ol/PluggableMap.js
+++ b/src/ol/PluggableMap.js
@@ -47,7 +47,7 @@ import {create as createTransform, apply as applyTransform} from './transform.js
  * @property {import("./size.js").Size} size
  * @property {!Object<string, boolean>} skippedFeatureUids
  * @property {TileQueue} tileQueue
- * @property {Object<string, Object<string, import("./TileRange.js").default>>} usedTiles
+ * @property {!Object<string, Object<string, boolean>>} usedTiles
  * @property {Array<number>} viewHints
  * @property {!Object<string, Object<string, boolean>>} wantedTiles
  */
diff --git a/src/ol/TileCache.js b/src/ol/TileCache.js
index 54b0cb4fd6..701e48e076 100644
--- a/src/ol/TileCache.js
+++ b/src/ol/TileCache.js
@@ -21,8 +21,7 @@ class TileCache extends LRUCache {
   expireCache(usedTiles) {
     while (this.canExpireCache()) {
       const tile = this.peekLast();
-      const zKey = tile.tileCoord[0].toString();
-      if (zKey in usedTiles && usedTiles[zKey].contains(tile.tileCoord)) {
+      if (tile.getKey() in usedTiles) {
         break;
       } else {
         this.pop().dispose();
diff --git a/src/ol/VectorRenderTile.js b/src/ol/VectorRenderTile.js
index 025e76c418..bc0c7ed4c7 100644
--- a/src/ol/VectorRenderTile.js
+++ b/src/ol/VectorRenderTile.js
@@ -103,6 +103,10 @@ class VectorRenderTile extends Tile {
    */
   disposeInternal() {
     this.removeSourceTiles_(this);
+    for (const key in this.context_) {
+      const canvas = this.context_[key].canvas;
+      canvas.width = canvas.height = 0;
+    }
     this.setState(TileState.ABORT);
     super.disposeInternal();
   }
diff --git a/src/ol/render/canvas.js b/src/ol/render/canvas.js
index bf6e314614..09a3c7696e 100644
--- a/src/ol/render/canvas.js
+++ b/src/ol/render/canvas.js
@@ -169,6 +169,17 @@ export const defaultLineWidth = 1;
 export const labelCache = new LRUCache();
 
 
+/**
+ * Prune the label cache.
+ */
+export function pruneLabelCache() {
+  while (labelCache.canExpireCache()) {
+    const canvas = labelCache.pop();
+    canvas.width = canvas.height = 0;
+  }
+}
+
+
 /**
  * @type {!Object<string, number>}
  */
diff --git a/src/ol/render/canvas/TextBuilder.js b/src/ol/render/canvas/TextBuilder.js
index e5850def1e..d77b62edf1 100644
--- a/src/ol/render/canvas/TextBuilder.js
+++ b/src/ol/render/canvas/TextBuilder.js
@@ -6,7 +6,7 @@ import {asColorLike} from '../../colorlike.js';
 import {intersects} from '../../extent.js';
 import {matchingChunk} from '../../geom/flat/straightchunk.js';
 import GeometryType from '../../geom/GeometryType.js';
-import {labelCache, defaultTextAlign, defaultPadding, defaultLineCap, defaultLineDashOffset, defaultLineDash, defaultLineJoin, defaultFillStyle, checkFont, defaultFont, defaultLineWidth, defaultMiterLimit, defaultStrokeStyle, defaultTextBaseline} from '../canvas.js';
+import {pruneLabelCache, defaultTextAlign, defaultPadding, defaultLineCap, defaultLineDashOffset, defaultLineDash, defaultLineJoin, defaultFillStyle, checkFont, defaultFont, defaultLineWidth, defaultMiterLimit, defaultStrokeStyle, defaultTextBaseline} from '../canvas.js';
 import CanvasInstruction from './Instruction.js';
 import CanvasBuilder from './Builder.js';
 import TextPlacement from '../../style/TextPlacement.js';
@@ -131,7 +131,7 @@ class CanvasTextBuilder extends CanvasBuilder {
      */
     this.strokeKey_ = '';
 
-    labelCache.prune();
+    pruneLabelCache();
   }
 
   /**
diff --git a/src/ol/renderer/Layer.js b/src/ol/renderer/Layer.js
index 3dd5682626..4d2249a180 100644
--- a/src/ol/renderer/Layer.js
+++ b/src/ol/renderer/Layer.js
@@ -192,26 +192,18 @@ class LayerRenderer extends Observable {
   }
 
   /**
-   * @param {!Object<string, !Object<string, import("../TileRange.js").default>>} usedTiles Used tiles.
+   * @param {!Object<string, !Object<string, boolean>>} usedTiles Used tiles.
    * @param {import("../source/Tile.js").default} tileSource Tile source.
-   * @param {number} z Z.
-   * @param {import("../TileRange.js").default} tileRange Tile range.
+   * @param {import('../Tile.js').default} tile Tile.
    * @protected
    */
-  updateUsedTiles(usedTiles, tileSource, z, tileRange) {
+  updateUsedTiles(usedTiles, tileSource, tile) {
     // FIXME should we use tilesToDrawByZ instead?
     const tileSourceKey = getUid(tileSource);
-    const zKey = z.toString();
-    if (tileSourceKey in usedTiles) {
-      if (zKey in usedTiles[tileSourceKey]) {
-        usedTiles[tileSourceKey][zKey].extend(tileRange);
-      } else {
-        usedTiles[tileSourceKey][zKey] = tileRange;
-      }
-    } else {
+    if (!(tileSourceKey in usedTiles)) {
       usedTiles[tileSourceKey] = {};
-      usedTiles[tileSourceKey][zKey] = tileRange;
     }
+    usedTiles[tileSourceKey][tile.getKey()] = true;
   }
 
   /**
diff --git a/src/ol/renderer/canvas/TileLayer.js b/src/ol/renderer/canvas/TileLayer.js
index 104ae39ad1..42c51e60e6 100644
--- a/src/ol/renderer/canvas/TileLayer.js
+++ b/src/ol/renderer/canvas/TileLayer.js
@@ -283,6 +283,7 @@ class CanvasTileLayerRenderer extends CanvasLayerRenderer {
 
         this.drawTileImage(tile, frameState, layerState, x, y, w, h, tileGutter, z === currentZ);
         this.renderedTiles.push(tile);
+        this.updateUsedTiles(frameState.usedTiles, tileSource, tile);
       }
     }
 
@@ -291,7 +292,6 @@ class CanvasTileLayerRenderer extends CanvasLayerRenderer {
     this.renderedResolution = tileResolution;
     this.renderedExtent_ = canvasExtent;
 
-    this.updateUsedTiles(frameState.usedTiles, tileSource, z, tileRange);
     this.manageTilePyramid(frameState, tileSource, tileGrid, pixelRatio,
       projection, extent, z, tileLayer.getPreload());
     this.scheduleExpireCache(frameState, tileSource);
diff --git a/src/ol/source/BingMaps.js b/src/ol/source/BingMaps.js
index 02f5b59783..7db6aa1fff 100644
--- a/src/ol/source/BingMaps.js
+++ b/src/ol/source/BingMaps.js
@@ -50,7 +50,7 @@ const TOS_ATTRIBUTION = '<a class="ol-attribution-bing-tos" ' +
 
 /**
  * @typedef {Object} Options
- * @property {number} [cacheSize=2048] Cache size.
+ * @property {number} [cacheSize] Tile cache size. Default is twice as many tiles as a fullscreen map needs.
  * @property {boolean} [hidpi=false] If `true` hidpi tiles will be requested.
  * @property {string} [culture='en-us'] Culture code.
  * @property {string} key Bing Maps API key. Get yours at http://www.bingmapsportal.com/.
diff --git a/src/ol/source/CartoDB.js b/src/ol/source/CartoDB.js
index cac2c71099..bcc5c329cc 100644
--- a/src/ol/source/CartoDB.js
+++ b/src/ol/source/CartoDB.js
@@ -9,7 +9,7 @@ import XYZ from './XYZ.js';
 /**
  * @typedef {Object} Options
  * @property {import("./Source.js").AttributionLike} [attributions] Attributions.
- * @property {number} [cacheSize=2048] Cache size.
+ * @property {number} [cacheSize] Tile cache size. Default is twice as many tiles as a fullscreen map needs.
  * @property {null|string} [crossOrigin] The `crossOrigin` attribute for loaded images.  Note that
  * you must provide a `crossOrigin` value if you want to access pixel data with the Canvas renderer.
  * See https://developer.mozilla.org/en-US/docs/Web/HTML/CORS_enabled_image for more detail.
diff --git a/src/ol/source/OSM.js b/src/ol/source/OSM.js
index f8ea4a341f..3c9d6a3850 100644
--- a/src/ol/source/OSM.js
+++ b/src/ol/source/OSM.js
@@ -20,7 +20,7 @@ export const ATTRIBUTION = '&#169; ' +
 /**
  * @typedef {Object} Options
  * @property {import("./Source.js").AttributionLike} [attributions] Attributions.
- * @property {number} [cacheSize=2048] Cache size.
+ * @property {number} [cacheSize] Tile cache size. Default is twice as many tiles as a fullscreen map needs.
  * @property {null|string} [crossOrigin] The `crossOrigin` attribute for loaded images.  Note that
  * you must provide a `crossOrigin` value if you want to access pixel data with the Canvas renderer.
  * See https://developer.mozilla.org/en-US/docs/Web/HTML/CORS_enabled_image for more detail.
diff --git a/src/ol/source/Stamen.js b/src/ol/source/Stamen.js
index cb76c5abf4..5188bd254c 100644
--- a/src/ol/source/Stamen.js
+++ b/src/ol/source/Stamen.js
@@ -90,7 +90,7 @@ const ProviderConfig = {
 
 /**
  * @typedef {Object} Options
- * @property {number} [cacheSize=2048] Cache size.
+ * @property {number} [cacheSize] Tile cache size. Default is twice as many tiles as a fullscreen map needs.
  * @property {string} layer Layer name.
  * @property {number} [minZoom] Minimum zoom.
  * @property {number} [maxZoom] Maximum zoom.
diff --git a/src/ol/source/Tile.js b/src/ol/source/Tile.js
index 5ca321b485..9a60057986 100644
--- a/src/ol/source/Tile.js
+++ b/src/ol/source/Tile.js
@@ -68,11 +68,23 @@ class TileSource extends Source {
      */
     this.tileGrid = options.tileGrid !== undefined ? options.tileGrid : null;
 
+    let cacheSize = options.cacheSize;
+    if (cacheSize === undefined) {
+      const tileSize = [256, 256];
+      const tileGrid = options.tileGrid;
+      if (tileGrid) {
+        toSize(tileGrid.getTileSize(tileGrid.getMinZoom()), tileSize);
+      }
+      const width = screen ? (screen.availWidth || screen.width) : 1920;
+      const height = screen ? (screen.availHeight || screen.height) : 1080;
+      cacheSize = 2 * Math.ceil(width / tileSize[0]) * Math.ceil(height / tileSize[1]);
+    }
+
     /**
      * @protected
      * @type {import("../TileCache.js").default}
      */
-    this.tileCache = new TileCache(options.cacheSize);
+    this.tileCache = new TileCache(cacheSize);
 
     /**
      * @protected
diff --git a/src/ol/source/TileArcGISRest.js b/src/ol/source/TileArcGISRest.js
index c76710a3d9..b14eac0654 100644
--- a/src/ol/source/TileArcGISRest.js
+++ b/src/ol/source/TileArcGISRest.js
@@ -13,7 +13,7 @@ import {appendParams} from '../uri.js';
 /**
  * @typedef {Object} Options
  * @property {import("./Source.js").AttributionLike} [attributions] Attributions.
- * @property {number} [cacheSize=2048] Cache size.
+ * @property {number} [cacheSize] Tile cache size. Default is twice as many tiles as a fullscreen map needs.
  * @property {null|string} [crossOrigin] The `crossOrigin` attribute for loaded images.  Note that
  * you must provide a `crossOrigin` value if you want to access pixel data with the Canvas renderer.
  * See https://developer.mozilla.org/en-US/docs/Web/HTML/CORS_enabled_image for more detail.
diff --git a/src/ol/source/TileImage.js b/src/ol/source/TileImage.js
index 8f9bfdcd66..9018265e5d 100644
--- a/src/ol/source/TileImage.js
+++ b/src/ol/source/TileImage.js
@@ -18,7 +18,7 @@ import {getForProjection as getTileGridForProjection} from '../tilegrid.js';
  * @typedef {Object} Options
  * @property {import("./Source.js").AttributionLike} [attributions] Attributions.
  * @property {boolean} [attributionsCollapsible=true] Attributions are collapsible.
- * @property {number} [cacheSize=2048] Cache size.
+ * @property {number} [cacheSize] Tile cache size. Default is twice as many tiles as a fullscreen map needs.
  * @property {null|string} [crossOrigin] The `crossOrigin` attribute for loaded images.  Note that
  * you must provide a `crossOrigin` value if you want to access pixel data with the Canvas renderer.
  * See https://developer.mozilla.org/en-US/docs/Web/HTML/CORS_enabled_image for more detail.
diff --git a/src/ol/source/TileJSON.js b/src/ol/source/TileJSON.js
index 537ab94cec..af2804837f 100644
--- a/src/ol/source/TileJSON.js
+++ b/src/ol/source/TileJSON.js
@@ -39,7 +39,7 @@ import {createXYZ, extentFromProjection} from '../tilegrid.js';
 /**
  * @typedef {Object} Options
  * @property {import("./Source.js").AttributionLike} [attributions] Attributions.
- * @property {number} [cacheSize=2048] Cache size.
+ * @property {number} [cacheSize] Tile cache size. Default is twice as many tiles as a fullscreen map needs.
  * @property {null|string} [crossOrigin] The `crossOrigin` attribute for loaded images.  Note that
  * you must provide a `crossOrigin` value if you want to access pixel data with the Canvas renderer.
  * See https://developer.mozilla.org/en-US/docs/Web/HTML/CORS_enabled_image for more detail.
diff --git a/src/ol/source/TileWMS.js b/src/ol/source/TileWMS.js
index 684c5108cc..8b0926c4c9 100644
--- a/src/ol/source/TileWMS.js
+++ b/src/ol/source/TileWMS.js
@@ -20,7 +20,7 @@ import {appendParams} from '../uri.js';
 /**
  * @typedef {Object} Options
  * @property {import("./Source.js").AttributionLike} [attributions] Attributions.
- * @property {number} [cacheSize=2048] Cache size.
+ * @property {number} [cacheSize] Tile cache size. Default is twice as many tiles as a fullscreen map needs.
  * @property {null|string} [crossOrigin] The `crossOrigin` attribute for loaded images.  Note that
  * you must provide a `crossOrigin` value if you want to access pixel data with the Canvas renderer.
  * See https://developer.mozilla.org/en-US/docs/Web/HTML/CORS_enabled_image for more detail.
diff --git a/src/ol/source/VectorTile.js b/src/ol/source/VectorTile.js
index d0d181336e..54269795be 100644
--- a/src/ol/source/VectorTile.js
+++ b/src/ol/source/VectorTile.js
@@ -96,7 +96,7 @@ class VectorTile extends UrlTile {
 
     super({
       attributions: options.attributions,
-      cacheSize: options.cacheSize !== undefined ? options.cacheSize : 128,
+      cacheSize: options.cacheSize,
       opaque: false,
       projection: projection,
       state: options.state,
diff --git a/src/ol/source/WMTS.js b/src/ol/source/WMTS.js
index 706a8de89a..18a36bc634 100644
--- a/src/ol/source/WMTS.js
+++ b/src/ol/source/WMTS.js
@@ -15,7 +15,7 @@ import {appendParams} from '../uri.js';
 /**
  * @typedef {Object} Options
  * @property {import("./Source.js").AttributionLike} [attributions] Attributions.
- * @property {number} [cacheSize=2048] Cache size.
+ * @property {number} [cacheSize] Tile cache size. Default is twice as many tiles as a fullscreen map needs.
  * @property {null|string} [crossOrigin] The `crossOrigin` attribute for loaded images.  Note that
  * you must provide a `crossOrigin` value if you want to access pixel data with the Canvas renderer.
  * See https://developer.mozilla.org/en-US/docs/Web/HTML/CORS_enabled_image for more detail.
diff --git a/src/ol/source/XYZ.js b/src/ol/source/XYZ.js
index d026760cb6..205b68f2e2 100644
--- a/src/ol/source/XYZ.js
+++ b/src/ol/source/XYZ.js
@@ -9,7 +9,7 @@ import {createXYZ, extentFromProjection} from '../tilegrid.js';
  * @typedef {Object} Options
  * @property {import("./Source.js").AttributionLike} [attributions] Attributions.
  * @property {boolean} [attributionsCollapsible=true] Attributions are collapsible.
- * @property {number} [cacheSize=2048] Cache size.
+ * @property {number} [cacheSize] Tile cache size. Default is twice as many tiles as a fullscreen map needs.
  * @property {null|string} [crossOrigin] The `crossOrigin` attribute for loaded images.  Note that
  * you must provide a `crossOrigin` value if you want to access pixel data with the Canvas renderer.
  * See https://developer.mozilla.org/en-US/docs/Web/HTML/CORS_enabled_image for more detail.
diff --git a/src/ol/source/Zoomify.js b/src/ol/source/Zoomify.js
index dbe476a64a..6b1076402b 100644
--- a/src/ol/source/Zoomify.js
+++ b/src/ol/source/Zoomify.js
@@ -82,7 +82,7 @@ export class CustomTile extends ImageTile {
 /**
  * @typedef {Object} Options
  * @property {import("./Source.js").AttributionLike} [attributions] Attributions.
- * @property {number} [cacheSize=2048] Cache size.
+ * @property {number} [cacheSize] Tile cache size. Default is twice as many tiles as a fullscreen map needs.
  * @property {null|string} [crossOrigin] The `crossOrigin` attribute for loaded images.  Note that
  * you must provide a `crossOrigin` value  you want to access pixel data with the Canvas renderer.
  * See https://developer.mozilla.org/en-US/docs/Web/HTML/CORS_enabled_image for more detail.
diff --git a/src/ol/structs/LRUCache.js b/src/ol/structs/LRUCache.js
index efed52b75f..d02241d405 100644
--- a/src/ol/structs/LRUCache.js
+++ b/src/ol/structs/LRUCache.js
@@ -287,16 +287,6 @@ class LRUCache extends EventTarget {
     this.highWaterMark = size;
   }
 
-
-  /**
-   * Prune the cache.
-   */
-  prune() {
-    while (this.canExpireCache()) {
-      this.pop();
-    }
-  }
-
 }
 
 export default LRUCache;
diff --git a/test/spec/ol/render/canvas/index.test.js b/test/spec/ol/render/canvas/index.test.js
index 7f178a37be..2cc763e545 100644
--- a/test/spec/ol/render/canvas/index.test.js
+++ b/test/spec/ol/render/canvas/index.test.js
@@ -10,6 +10,17 @@ describe('ol.render.canvas', function() {
   font.rel = 'stylesheet';
   const head = document.getElementsByTagName('head')[0];
 
+  it('pruneLabelCache()', function() {
+    const highWaterMark = render.labelCache.highWaterMark;
+    render.labelCache.highWaterMark = 1;
+    render.labelCache.set('foo', document.createElement('canvas'));
+    render.labelCache.set('bar', document.createElement('canvas'));
+    render.pruneLabelCache();
+    expect(render.labelCache.getCount()).to.be(1);
+    render.labelCache.highWaterMark = highWaterMark;
+    render.labelCache.clear();
+  });
+
   describe('ol.render.canvas.checkFont()', function() {
 
     beforeEach(function() {
diff --git a/test/spec/ol/structs/lrucache.test.js b/test/spec/ol/structs/lrucache.test.js
index 9111bce71b..2a9842dfbf 100644
--- a/test/spec/ol/structs/lrucache.test.js
+++ b/test/spec/ol/structs/lrucache.test.js
@@ -285,7 +285,9 @@ describe('ol.structs.LRUCache', function() {
       lruCache.setSize(2);
       expect(lruCache.highWaterMark).to.be(2);
       fillLRUCache(lruCache);
-      lruCache.prune();
+      while (lruCache.canExpireCache()) {
+        lruCache.pop();
+      }
       expect(lruCache.getKeys().length).to.be(2);
     });
   });