--- a/client/src/components/Pdftool.vue	Fri Jun 19 16:19:57 2020 +0200
+++ b/client/src/components/Pdftool.vue	Fri Jun 26 11:37:20 2020 +0200
@@ -59,7 +59,7 @@
           </small>
           <input
             class="form-control form-control-sm w-100 ml-2"
-            placeholder="10000"
+            :placeholder="scalePlaceholder"
             v-model.number="form.scale"
             type="number"
           />
@@ -219,6 +219,13 @@
         }
       });
       return counter;
+    },
+    scalePlaceholder() {
+      if (typeof this.openLayersMap() !== "undefined") {
+        return this.calculateScaleDenominator();
+      } else {
+        return "10000";
+      }
     }
   },
   methods: {
@@ -339,21 +346,9 @@
        *
        */
       this.readyToGenerate = false;
-      if (this.form.format !== "portrait") {
-        this.pdf.width = paperSizes[this.form.paperSize][0];
-        this.pdf.height = paperSizes[this.form.paperSize][1];
-      } else {
-        this.pdf.width = paperSizes[this.form.paperSize][1];
-        this.pdf.height = paperSizes[this.form.paperSize][0];
-      }
-
+      this.setPDFDimension();
       // FUTURE: consider margins
-
-      var pixelsPerMapMillimeter = this.form.resolution / 25.4;
-      var mapSizeForPrint = [
-        Math.round(this.pdf.width * pixelsPerMapMillimeter),
-        Math.round(this.pdf.height * pixelsPerMapMillimeter)
-      ];
+      const mapSizeForPrint = this.setMapSizForPrint();
       var map = this.openLayersMap();
       this.mapSize = map.getSize();
       this.resolution = map.getView().getResolution();
@@ -361,15 +356,7 @@
       this.pdf.doc = new jsPDF(this.form.format, "mm", this.form.paperSize);
       this.rendercompleteListener = map.once("rendercomplete", event => {
         let canvas = event.context.canvas;
-        let scaleDenominator = Math.round(
-          1000 *
-            pixelsPerMapMillimeter *
-            this.getMeterPerPixel(
-              this.openLayersMap()
-                .getView()
-                .getResolution()
-            )
-        );
+        let scaleDenominator = this.calculateScaleDenominator();
         var snapshot = canvas.toDataURL("image/jpeg");
         this.pdf.doc.addImage(
           snapshot,
@@ -911,6 +898,50 @@
           textOptions
         );
       }
+    },
+    calculateScaleDenominator() {
+      const pixelsPerMapMillimeter = this.form.resolution / 25.4;
+      if (!this.form.scale) {
+        this.setPDFDimension();
+        const mapSizeForPrint = this.setMapSizForPrint();
+        const size = this.openLayersMap().getSize();
+        const [width, height] = mapSizeForPrint;
+        const scaling = Math.min(width / size[0], height / size[1]);
+        return Math.round(
+          1000 *
+            pixelsPerMapMillimeter *
+            this.getMeterPerPixel(
+              this.openLayersMap()
+                .getView()
+                .getResolution() / scaling
+            )
+        );
+      }
+      return Math.round(
+        1000 *
+          pixelsPerMapMillimeter *
+          this.getMeterPerPixel(
+            this.openLayersMap()
+              .getView()
+              .getResolution()
+          )
+      );
+    },
+    setPDFDimension() {
+      if (this.form.format !== "portrait") {
+        this.pdf.width = paperSizes[this.form.paperSize][0];
+        this.pdf.height = paperSizes[this.form.paperSize][1];
+      } else {
+        this.pdf.width = paperSizes[this.form.paperSize][1];
+        this.pdf.height = paperSizes[this.form.paperSize][0];
+      }
+    },
+    setMapSizForPrint() {
+      const pixelsPerMapMillimeter = this.form.resolution / 25.4;
+      return [
+        Math.round(this.pdf.width * pixelsPerMapMillimeter),
+        Math.round(this.pdf.height * pixelsPerMapMillimeter)
+      ];
     }
   },
   mounted() {