diff --git a/src/lib/progress-spinner/progress-spinner.html b/src/lib/progress-spinner/progress-spinner.html
index 4de40c2dca21..cb5f8db64b44 100644
--- a/src/lib/progress-spinner/progress-spinner.html
+++ b/src/lib/progress-spinner/progress-spinner.html
@@ -6,8 +6,8 @@
 -->
 
 <svg
-  [style.width.px]="_elementSize"
-  [style.height.px]="_elementSize"
+  [style.width.px]="diameter"
+  [style.height.px]="diameter"
   [attr.viewBox]="_viewBox"
   preserveAspectRatio="xMidYMid meet"
   focusable="false">
diff --git a/src/lib/progress-spinner/progress-spinner.spec.ts b/src/lib/progress-spinner/progress-spinner.spec.ts
index d00d31881999..e5edabe4d411 100644
--- a/src/lib/progress-spinner/progress-spinner.spec.ts
+++ b/src/lib/progress-spinner/progress-spinner.spec.ts
@@ -140,7 +140,7 @@ describe('MatProgressSpinner', () => {
     fixture.componentInstance.strokeWidth = 40;
     fixture.detectChanges();
 
-    expect(parseInt(circleElement.style.strokeWidth)).toBe(30, 'Expected the custom stroke ' +
+    expect(parseInt(circleElement.style.strokeWidth)).toBe(40, 'Expected the custom stroke ' +
       'width to be applied to the circle element as a percentage of the element size.');
     expect(svgElement.getAttribute('viewBox'))
       .toBe('0 0 130 130', 'Expected the viewBox to be adjusted based on the stroke width.');
@@ -153,8 +153,8 @@ describe('MatProgressSpinner', () => {
     fixture.componentInstance.strokeWidth = 40;
     fixture.detectChanges();
 
-    expect(element.style.width).toBe('130px');
-    expect(element.style.height).toBe('130px');
+    expect(element.style.width).toBe('100px');
+    expect(element.style.height).toBe('100px');
   });
 
   it('should not collapse the host element if the stroke width is less than the default', () => {
@@ -217,10 +217,10 @@ describe('MatProgressSpinner', () => {
     expect(spinner.componentInstance.strokeWidth).toBe(11);
     expect(spinner.componentInstance.value).toBe(25);
 
-    expect(spinner.nativeElement.style.width).toBe('38px');
-    expect(spinner.nativeElement.style.height).toBe('38px');
-    expect(svgElement.style.width).toBe('38px');
-    expect(svgElement.style.height).toBe('38px');
+    expect(spinner.nativeElement.style.width).toBe('37px');
+    expect(spinner.nativeElement.style.height).toBe('37px');
+    expect(svgElement.style.width).toBe('37px');
+    expect(svgElement.style.height).toBe('37px');
     expect(svgElement.getAttribute('viewBox')).toBe('0 0 38 38');
   });
 
diff --git a/src/lib/progress-spinner/progress-spinner.ts b/src/lib/progress-spinner/progress-spinner.ts
index 509e42794578..dc7b88885c33 100644
--- a/src/lib/progress-spinner/progress-spinner.ts
+++ b/src/lib/progress-spinner/progress-spinner.ts
@@ -11,8 +11,6 @@ import {
   ChangeDetectionStrategy,
   Input,
   ElementRef,
-  SimpleChanges,
-  OnChanges,
   ViewEncapsulation,
   Optional,
   Inject,
@@ -82,8 +80,8 @@ const INDETERMINATE_ANIMATION_TEMPLATE = `
   host: {
     'role': 'progressbar',
     'class': 'mat-progress-spinner',
-    '[style.width.px]': '_elementSize',
-    '[style.height.px]': '_elementSize',
+    '[style.width.px]': 'diameter',
+    '[style.height.px]': 'diameter',
     '[attr.aria-valuemin]': 'mode === "determinate" ? 0 : null',
     '[attr.aria-valuemax]': 'mode === "determinate" ? 100 : null',
     '[attr.aria-valuenow]': 'value',
@@ -95,16 +93,12 @@ const INDETERMINATE_ANIMATION_TEMPLATE = `
   changeDetection: ChangeDetectionStrategy.OnPush,
   encapsulation: ViewEncapsulation.None,
 })
-export class MatProgressSpinner extends _MatProgressSpinnerMixinBase implements CanColor,
-  OnChanges {
+export class MatProgressSpinner extends _MatProgressSpinnerMixinBase implements CanColor {
 
   private _value = 0;
   private _strokeWidth: number;
   private _fallbackAnimation = false;
 
-  /** The width and height of the host element. Will grow with stroke width. */
-  _elementSize = BASE_SIZE;
-
   /** Tracks diameters of existing instances to de-dupe generated styles (default d = 100) */
   private static diameters = new Set<number>([BASE_SIZE]);
 
@@ -123,7 +117,6 @@ export class MatProgressSpinner extends _MatProgressSpinnerMixinBase implements
     if (!this._fallbackAnimation && !MatProgressSpinner.diameters.has(this._diameter)) {
       this._attachStyleNode();
     }
-    this._updateElementSize();
   }
   private _diameter = BASE_SIZE;
 
@@ -164,12 +157,6 @@ export class MatProgressSpinner extends _MatProgressSpinnerMixinBase implements
     _elementRef.nativeElement.classList.add(animationClass);
   }
 
-  ngOnChanges(changes: SimpleChanges) {
-    if (changes.strokeWidth || changes.diameter) {
-      this._updateElementSize();
-    }
-  }
-
   /** The radius of the spinner, adjusted for stroke width. */
   get _circleRadius() {
     return (this.diameter - BASE_STROKE_WIDTH) / 2;
@@ -202,7 +189,7 @@ export class MatProgressSpinner extends _MatProgressSpinnerMixinBase implements
 
   /** Stroke width of the circle in percent. */
   get _circleStrokeWidth() {
-    return this.strokeWidth / this._elementSize * 100;
+    return this.strokeWidth / this.diameter * 100;
   }
 
   /** Dynamically generates a style tag containing the correct animation for this diameter. */
@@ -230,11 +217,6 @@ export class MatProgressSpinner extends _MatProgressSpinnerMixinBase implements
         .replace(/END_VALUE/g, `${0.2 * this._strokeCircumference}`)
         .replace(/DIAMETER/g, `${this.diameter}`);
   }
-
-  /** Updates the spinner element size based on its diameter. */
-  private _updateElementSize() {
-    this._elementSize = this._diameter + Math.max(this.strokeWidth - BASE_STROKE_WIDTH, 0);
-  }
 }
 
 
@@ -251,8 +233,8 @@ export class MatProgressSpinner extends _MatProgressSpinnerMixinBase implements
     'role': 'progressbar',
     'mode': 'indeterminate',
     'class': 'mat-spinner mat-progress-spinner',
-    '[style.width.px]': '_elementSize',
-    '[style.height.px]': '_elementSize',
+    '[style.width.px]': 'diameter',
+    '[style.height.px]': 'diameter',
   },
   inputs: ['color'],
   templateUrl: 'progress-spinner.html',