diff --git a/src/lib/directives/ng2-fittext.directive.ts b/src/lib/directives/ng2-fittext.directive.ts
index 24ee24e..331783c 100644
--- a/src/lib/directives/ng2-fittext.directive.ts
+++ b/src/lib/directives/ng2-fittext.directive.ts
@@ -29,13 +29,13 @@ export class Ng2FittextDirective
 
   @Input('modelToWatch') modelToWatch: any;
 
-  @Output() fontSizeChanged: EventEmitter<any> = new EventEmitter();
+  @Output() fontSizeChanged: EventEmitter<number> = new EventEmitter();
 
   private fontSize = 1000;
   private speed = 1.05;
   private done = false;
 
-  constructor(public el: ElementRef, public renderer: Renderer2) {}
+  constructor(public el: ElementRef<HTMLElement>, public renderer: Renderer2) {}
 
   setFontSize(fontSize: number): void {
     if (this.isVisible() && !this.isDone()) {
@@ -62,10 +62,19 @@ export class Ng2FittextDirective
     return Math.floor(fontSize / speed);
   }
 
-  checkOverflow(parent: any, children: any): boolean {
-    const overflowX = children.scrollWidth - parent.clientWidth;
-    const overflowY = children.clientHeight - parent.clientHeight;
-    return overflowX > 1 || overflowY > 1;
+  checkOverflow(parent: HTMLElement, children: HTMLElement): boolean {
+    return (
+      this.hasXAxisOverflow(parent, children) ||
+      this.hasYAxisOverflow(parent, children)
+    );
+  }
+
+  hasXAxisOverflow(parent: HTMLElement, children: HTMLElement): boolean {
+    return children.scrollWidth - parent.clientWidth > 0;
+  }
+
+  hasYAxisOverflow(parent: HTMLElement, children: HTMLElement): boolean {
+    return children.clientHeight - parent.clientHeight > 0;
   }
 
   @HostListener('window:resize', ['$event'])
@@ -100,13 +109,7 @@ export class Ng2FittextDirective
   ngAfterViewInit() {
     if (this.isVisible() && !this.isDone()) {
       if (this.fittext) {
-        const overflow = this.container
-          ? this.checkOverflow(this.container, this.el.nativeElement)
-          : this.checkOverflow(
-              this.el.nativeElement.parentElement,
-              this.el.nativeElement
-            );
-        if (overflow) {
+        if (this.hasOverflow()) {
           if (this.fontSize > this.minFontSize) {
             // iterate only until font size is bigger than minimal value
             this.setFontSize(this.calculateFontSize(this.fontSize, this.speed));
@@ -156,4 +159,13 @@ export class Ng2FittextDirective
   isVisible(): boolean {
     return this.getStartFontSizeFromHeight() > 0;
   }
+
+  hasOverflow(): boolean {
+    return this.container
+      ? this.checkOverflow(this.container, this.el.nativeElement)
+      : this.checkOverflow(
+          this.el.nativeElement.parentElement,
+          this.el.nativeElement
+        );
+  }
 }
diff --git a/src/lib/directives/specs/ng2-fittext.directive.spec.ts b/src/lib/directives/specs/ng2-fittext.directive.spec.ts
index 32c2ce7..f1f26ba 100644
--- a/src/lib/directives/specs/ng2-fittext.directive.spec.ts
+++ b/src/lib/directives/specs/ng2-fittext.directive.spec.ts
@@ -101,18 +101,22 @@ describe('Class: Ng2FittextDirective', () => {
   });
 
   describe('Method: checkOverflow', () => {
-    let parentElementMock: any;
-    let childrenElementMock: any;
+    let parentElementMock: HTMLElement;
+    let childrenElementMock: HTMLElement;
+    let hasXAxisOverflowSpy: jasmine.Spy;
+    let hasYAxisOverflowSpy: jasmine.Spy;
 
     beforeEach(() => {
-      parentElementMock = {
-        clientWidth: 0,
-        clientHeight: 0,
-      };
-      childrenElementMock = {
-        scrollWidth: 0,
-        clientHeight: 0,
-      };
+      parentElementMock = {} as HTMLElement;
+      childrenElementMock = {} as HTMLElement;
+      hasXAxisOverflowSpy = spyOn(
+        ng2FittextDirective,
+        'hasXAxisOverflow'
+      ).and.returnValue(false);
+      hasYAxisOverflowSpy = spyOn(
+        ng2FittextDirective,
+        'hasYAxisOverflow'
+      ).and.returnValue(false);
     });
 
     it('Should return false if no overflow is present', () => {
@@ -125,7 +129,7 @@ describe('Class: Ng2FittextDirective', () => {
     });
 
     it('Should return true if x axis has overflow', () => {
-      childrenElementMock.scrollWidth = 2;
+      hasXAxisOverflowSpy.and.returnValue(true);
       expect(
         ng2FittextDirective.checkOverflow(
           parentElementMock,
@@ -135,7 +139,7 @@ describe('Class: Ng2FittextDirective', () => {
     });
 
     it('Should return true if y axis has overflow', () => {
-      childrenElementMock.clientHeight = 2;
+      hasYAxisOverflowSpy.and.returnValue(true);
       expect(
         ng2FittextDirective.checkOverflow(
           parentElementMock,
@@ -194,4 +198,113 @@ describe('Class: Ng2FittextDirective', () => {
       expect(ng2FittextDirective.isVisible()).toBe(false);
     });
   });
+
+  describe('Method: hasXAxisOverflow', () => {
+    let parentElementMock: HTMLElement;
+    let childrenElementMock: HTMLElement;
+
+    beforeEach(() => {
+      parentElementMock = {
+        clientWidth: 0,
+      } as HTMLElement;
+      childrenElementMock = {
+        scrollWidth: 0,
+      } as HTMLElement;
+    });
+
+    it('Should return false if no overflow is present on the x axis', () => {
+      expect(
+        ng2FittextDirective.hasXAxisOverflow(
+          parentElementMock,
+          childrenElementMock
+        )
+      ).toBe(false);
+    });
+
+    it('Should return true if overflow is present on the x axis', () => {
+      childrenElementMock = {
+        scrollWidth: 2,
+      } as HTMLElement;
+      expect(
+        ng2FittextDirective.hasXAxisOverflow(
+          parentElementMock,
+          childrenElementMock
+        )
+      ).toBe(true);
+    });
+  });
+
+  describe('Method: hasYAxisOverflow', () => {
+    let parentElementMock: HTMLElement;
+    let childrenElementMock: HTMLElement;
+
+    beforeEach(() => {
+      parentElementMock = {
+        clientHeight: 0,
+      } as HTMLElement;
+      childrenElementMock = {
+        clientHeight: 0,
+      } as HTMLElement;
+    });
+
+    it('Should return false if no overflow is present on the x axis', () => {
+      expect(
+        ng2FittextDirective.hasYAxisOverflow(
+          parentElementMock,
+          childrenElementMock
+        )
+      ).toBe(false);
+    });
+
+    it('Should return true if overflow is present on the x axis', () => {
+      childrenElementMock = {
+        clientHeight: 2,
+      } as HTMLElement;
+      expect(
+        ng2FittextDirective.hasYAxisOverflow(
+          parentElementMock,
+          childrenElementMock
+        )
+      ).toBe(true);
+    });
+  });
+
+  describe('Method: hasOverflow', () => {
+    let containerMock: any;
+    let parentElementMock: any;
+
+    beforeEach(() => {
+      containerMock = {
+        isContainer: true,
+      };
+      parentElementMock = {
+        isParentElement: true,
+      };
+      ng2FittextDirective.container = { ...containerMock };
+      ng2FittextDirective.el.nativeElement = {
+        parentElement: { ...parentElementMock },
+      } as HTMLElement;
+    });
+
+    it('Should calculate the overflow using the container if is present', () => {
+      spyOn(ng2FittextDirective, 'checkOverflow').and.callFake(
+        (parentElement: any, childrenElement: any) => {
+          expect(parentElement).toEqual(containerMock);
+          return true;
+        }
+      );
+      expect(ng2FittextDirective.hasOverflow()).toBe(true);
+    });
+
+    it('Should calculate the overflow using the parent element if the container is not present', () => {
+      delete ng2FittextDirective.container;
+      spyOn(ng2FittextDirective, 'checkOverflow').and.callFake(
+        (parentElement: any, childrenElement: any) => {
+          expect(parentElement).toEqual(parentElementMock);
+          return true;
+        }
+      );
+      expect(ng2FittextDirective.hasOverflow()).toBe(true);
+    });
+  });
 });