diff --git a/src/lib/directives/ng2-fittext.directive.ts b/src/lib/directives/ng2-fittext.directive.ts
index 2c435b8..24ee24e 100644
--- a/src/lib/directives/ng2-fittext.directive.ts
+++ b/src/lib/directives/ng2-fittext.directive.ts
@@ -137,7 +137,7 @@ export class Ng2FittextDirective
     }
   }
 
-  private getStartFontSizeFromHeight(): number {
+  getStartFontSizeFromHeight(): number {
     return this.container
       ? this.container.clientHeight
       : this.el.nativeElement.parentElement.clientHeight;
diff --git a/src/lib/directives/specs/ng2-fittext.directive.spec.ts b/src/lib/directives/specs/ng2-fittext.directive.spec.ts
index 84ecdc3..872cfc5 100644
--- a/src/lib/directives/specs/ng2-fittext.directive.spec.ts
+++ b/src/lib/directives/specs/ng2-fittext.directive.spec.ts
@@ -144,4 +144,28 @@ describe('Class: Ng2FittextDirective', () => {
       ).toBe(true);
     });
   });
+
+  describe('Method: getStartFontSizeFromHeight', () => {
+    it('Should return the container clientHeight value if the container is present', () => {
+      const containerClientHeight = 10;
+      ng2FittextDirective.container = {
+        clientHeight: containerClientHeight,
+      } as HTMLElement;
+      expect(ng2FittextDirective.getStartFontSizeFromHeight()).toEqual(
+        containerClientHeight
+      );
+    });
+
+    it('Should return the parentElement clientHeight value if no container is present', () => {
+      const parentlientHeight = 11;
+      elMock.nativeElement = {
+        parentElement: {
+          clientHeight: parentlientHeight,
+        },
+      } as HTMLElement;
+      expect(ng2FittextDirective.getStartFontSizeFromHeight()).toEqual(
+        parentlientHeight
+      );
+    });
+  });
 });