diff --git a/packages/angular_devkit/build_angular/src/angular-cli-files/plugins/bundle-budget.ts b/packages/angular_devkit/build_angular/src/angular-cli-files/plugins/bundle-budget.ts
index 6400ce9491b9..4ee676886846 100644
--- a/packages/angular_devkit/build_angular/src/angular-cli-files/plugins/bundle-budget.ts
+++ b/packages/angular_devkit/build_angular/src/angular-cli-files/plugins/bundle-budget.ts
@@ -1,6 +1,3 @@
-// tslint:disable
-// TODO: cleanup this file, it's copied as is from Angular CLI.
-
 /**
  * @license
  * Copyright Google Inc. All Rights Reserved.
@@ -8,9 +5,9 @@
  * Use of this source code is governed by an MIT-style license that can be
  * found in the LICENSE file at https://angular.io/license
  */
-
-import { Size, calculateBytes, calculateSizes } from '../utilities/bundle-calculator';
+import { Compiler, compilation } from 'webpack';
 import { Budget } from '../../browser/schema';
+import { Size, calculateBytes, calculateSizes } from '../utilities/bundle-calculator';
 import { formatSize } from '../utilities/stats';
 
 interface Thresholds {
@@ -31,19 +28,20 @@ export interface BundleBudgetPluginOptions {
 export class BundleBudgetPlugin {
   constructor(private options: BundleBudgetPluginOptions) { }
 
-  apply(compiler: any): void {
+  apply(compiler: Compiler): void {
     const { budgets } = this.options;
-    compiler.hooks.afterEmit.tap('BundleBudgetPlugin', (compilation: any) => {
+    compiler.hooks.afterEmit.tap('BundleBudgetPlugin', (compilation: compilation.Compilation) => {
       if (!budgets || budgets.length === 0) {
         return;
       }
 
       budgets.map(budget => {
         const thresholds = this.calculate(budget);
+
         return {
           budget,
           thresholds,
-          sizes: calculateSizes(budget, compilation)
+          sizes: calculateSizes(budget, compilation),
         };
       })
         .forEach(budgetCheck => {
@@ -62,7 +60,7 @@ export class BundleBudgetPlugin {
     });
   }
 
-  private checkMinimum(threshold: number | undefined, size: Size, messages: any) {
+  private checkMinimum(threshold: number | undefined, size: Size, messages: string[]) {
     if (threshold) {
       if (threshold > size.size) {
         const sizeDifference = formatSize(threshold - size.size);
@@ -72,7 +70,7 @@ export class BundleBudgetPlugin {
     }
   }
 
-  private checkMaximum(threshold: number | undefined, size: Size, messages: any) {
+  private checkMaximum(threshold: number | undefined, size: Size, messages: string[]) {
     if (threshold) {
       if (threshold < size.size) {
         const sizeDifference = formatSize(size.size - threshold);
@@ -83,37 +81,37 @@ export class BundleBudgetPlugin {
   }
 
   private calculate(budget: Budget): Thresholds {
-    let thresholds: Thresholds = {};
+    const thresholds: Thresholds = {};
     if (budget.maximumWarning) {
-      thresholds.maximumWarning = calculateBytes(budget.maximumWarning, budget.baseline, 'pos');
+      thresholds.maximumWarning = calculateBytes(budget.maximumWarning, budget.baseline, 1);
     }
 
     if (budget.maximumError) {
-      thresholds.maximumError = calculateBytes(budget.maximumError, budget.baseline, 'pos');
+      thresholds.maximumError = calculateBytes(budget.maximumError, budget.baseline, 1);
     }
 
     if (budget.minimumWarning) {
-      thresholds.minimumWarning = calculateBytes(budget.minimumWarning, budget.baseline, 'neg');
+      thresholds.minimumWarning = calculateBytes(budget.minimumWarning, budget.baseline, -1);
     }
 
     if (budget.minimumError) {
-      thresholds.minimumError = calculateBytes(budget.minimumError, budget.baseline, 'neg');
+      thresholds.minimumError = calculateBytes(budget.minimumError, budget.baseline, -1);
     }
 
     if (budget.warning) {
-      thresholds.warningLow = calculateBytes(budget.warning, budget.baseline, 'neg');
+      thresholds.warningLow = calculateBytes(budget.warning, budget.baseline, -1);
     }
 
     if (budget.warning) {
-      thresholds.warningHigh = calculateBytes(budget.warning, budget.baseline, 'pos');
+      thresholds.warningHigh = calculateBytes(budget.warning, budget.baseline, 1);
     }
 
     if (budget.error) {
-      thresholds.errorLow = calculateBytes(budget.error, budget.baseline, 'neg');
+      thresholds.errorLow = calculateBytes(budget.error, budget.baseline, -1);
     }
 
     if (budget.error) {
-      thresholds.errorHigh = calculateBytes(budget.error, budget.baseline, 'pos');
+      thresholds.errorHigh = calculateBytes(budget.error, budget.baseline, 1);
     }
 
     return thresholds;
diff --git a/packages/angular_devkit/build_angular/src/angular-cli-files/utilities/bundle-calculator.ts b/packages/angular_devkit/build_angular/src/angular-cli-files/utilities/bundle-calculator.ts
index 810899e0d868..745fb6ac97dd 100644
--- a/packages/angular_devkit/build_angular/src/angular-cli-files/utilities/bundle-calculator.ts
+++ b/packages/angular_devkit/build_angular/src/angular-cli-files/utilities/bundle-calculator.ts
@@ -1,6 +1,3 @@
-// tslint:disable
-// TODO: cleanup this file, it's copied as is from Angular CLI.
-
 /**
  * @license
  * Copyright Google Inc. All Rights Reserved.
@@ -11,8 +8,8 @@
 import { Budget } from '../../browser/schema';
 
 export interface Compilation {
-  assets: any;
-  chunks: any[];
+  assets: { [name: string]: { size: () => number } };
+  chunks: { name: string, files: string[], isOnlyInitial: () => boolean }[];
   warnings: string[];
   errors: string[];
 }
@@ -33,6 +30,7 @@ export function calculateSizes(budget: Budget, compilation: Compilation): Size[]
   };
   const ctor = calculatorMap[budget.type];
   const calculator = new ctor(budget, compilation);
+
   return calculator.calculate();
 }
 
@@ -52,6 +50,7 @@ class BundleCalculator extends Calculator {
       .reduce((files, chunk) => [...files, ...chunk.files], [])
       .map((file: string) => this.compilation.assets[file].size())
       .reduce((total: number, size: number) => total + size, 0);
+
     return [{size, label: this.budget.name}];
   }
 }
@@ -66,6 +65,7 @@ class InitialCalculator extends Calculator {
       .reduce((files, chunk) => [...files, ...chunk.files], [])
       .map((file: string) => this.compilation.assets[file].size())
       .reduce((total: number, size: number) => total + size, 0);
+
     return [{size, label: 'initial'}];
   }
 }
@@ -80,6 +80,7 @@ class AllScriptCalculator extends Calculator {
       .map(key => this.compilation.assets[key])
       .map(asset => asset.size())
       .reduce((total: number, size: number) => total + size, 0);
+
     return [{size, label: 'total scripts'}];
   }
 }
@@ -92,6 +93,7 @@ class AllCalculator extends Calculator {
     const size: number = Object.keys(this.compilation.assets)
       .map(key => this.compilation.assets[key].size())
       .reduce((total: number, size: number) => total + size, 0);
+
     return [{size, label: 'total'}];
   }
 }
@@ -105,9 +107,10 @@ class AnyScriptCalculator extends Calculator {
       .filter(key => /\.js$/.test(key))
       .map(key => {
         const asset = this.compilation.assets[key];
+
         return {
           size: asset.size(),
-          label: key
+          label: key,
         };
       });
   }
@@ -121,9 +124,10 @@ class AnyCalculator extends Calculator {
     return Object.keys(this.compilation.assets)
       .map(key => {
         const asset = this.compilation.assets[key];
+
         return {
           size: asset.size(),
-          label: key
+          label: key,
         };
       });
   }
@@ -132,39 +136,33 @@ class AnyCalculator extends Calculator {
 /**
  * Calculate the bytes given a string value.
  */
-export function calculateBytes(val: string, baseline?: string, factor?: ('pos' | 'neg')): number {
-  if (/^\d+$/.test(val)) {
-    return parseFloat(val);
+export function calculateBytes(
+  input: string,
+  baseline?: string,
+  factor: 1 | -1 = 1,
+): number {
+  const matches = input.match(/^\s*(\d+(?:\.\d+)?)\s*(%|(?:[mM]|[kK]|[gG])?[bB])?\s*$/);
+  if (!matches) {
+    return NaN;
   }
 
-  if (/^(\d+)%$/.test(val)) {
-    return calculatePercentBytes(val, baseline, factor);
+  const baselineBytes = baseline && calculateBytes(baseline) || 0;
+
+  let value = Number(matches[1]);
+  switch (matches[2] && matches[2].toLowerCase()) {
+    case '%':
+      value = baselineBytes * value / 100 * factor;
+      break;
+    case 'kb':
+      value *= 1024;
+      break;
+    case 'mb':
+      value *= 1024 * 1024;
+      break;
+    case 'gb':
+      value *= 1024 * 1024 * 1024;
+      break;
   }
 
-  const multiplier = getMultiplier(val);
-
-  const numberVal = parseFloat(val.replace(/((k|m|M|)b?)$/, ''));
-  const baselineVal = baseline ? parseFloat(baseline.replace(/((k|m|M|)b?)$/, '')) : 0;
-  const baselineMultiplier = baseline ? getMultiplier(baseline) : 1;
-  const factorMultiplier = factor ? (factor === 'pos' ? 1 : -1) : 1;
-
-  return numberVal * multiplier + baselineVal * baselineMultiplier * factorMultiplier;
-}
-
-function getMultiplier(val: string): number {
-  if (/^(\d+)b?$/.test(val)) {
-    return 1;
-  } else if (/^(\d+)kb$/.test(val)) {
-    return 1000;
-  } else if (/^(\d+)(m|M)b$/.test(val)) {
-    return 1000 * 1000;
-  } else {
-    return 1;
-  }
-}
-
-function calculatePercentBytes(val: string, baseline?: string, factor?: ('pos' | 'neg')): number {
-  const baselineBytes = calculateBytes(baseline as string);
-  const percentage = parseFloat(val.replace(/%/g, ''));
-  return baselineBytes + baselineBytes * percentage / 100 * (factor === 'pos' ? 1 : -1);
+  return value + baselineBytes;
 }
diff --git a/packages/angular_devkit/build_angular/src/angular-cli-files/utilities/bundle-calculator_spec.ts b/packages/angular_devkit/build_angular/src/angular-cli-files/utilities/bundle-calculator_spec.ts
new file mode 100644
index 000000000000..c610706ebe0c
--- /dev/null
+++ b/packages/angular_devkit/build_angular/src/angular-cli-files/utilities/bundle-calculator_spec.ts
@@ -0,0 +1,80 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+import { calculateBytes } from './bundle-calculator';
+
+describe('bundle-calculator', () => {
+  it('converts an integer with no postfix', () => {
+    expect(calculateBytes('0')).toBe(0);
+    expect(calculateBytes('5')).toBe(5);
+    expect(calculateBytes('190')).toBe(190);
+    expect(calculateBytes('92')).toBe(92);
+  });
+
+  it('converts a decimal with no postfix', () => {
+    expect(calculateBytes('3.14')).toBe(3.14);
+    expect(calculateBytes('0.25')).toBe(0.25);
+    expect(calculateBytes('90.5')).toBe(90.5);
+    expect(calculateBytes('25.0')).toBe(25);
+  });
+
+  it('converts an integer with kb postfix', () => {
+    expect(calculateBytes('0kb')).toBe(0);
+    expect(calculateBytes('5kb')).toBe(5 * 1024);
+    expect(calculateBytes('190KB')).toBe(190 * 1024);
+    expect(calculateBytes('92Kb')).toBe(92 * 1024);
+    expect(calculateBytes('25kB')).toBe(25 * 1024);
+  });
+
+  it('converts a decimal with kb postfix', () => {
+    expect(calculateBytes('3.14kb')).toBe(3.14 * 1024);
+    expect(calculateBytes('0.25KB')).toBe(0.25 * 1024);
+    expect(calculateBytes('90.5Kb')).toBe(90.5 * 1024);
+    expect(calculateBytes('25.0kB')).toBe(25 * 1024);
+  });
+
+  it('converts an integer with mb postfix', () => {
+    expect(calculateBytes('0mb')).toBe(0);
+    expect(calculateBytes('5mb')).toBe(5 * 1024 * 1024);
+    expect(calculateBytes('190MB')).toBe(190 * 1024 * 1024);
+    expect(calculateBytes('92Mb')).toBe(92 * 1024 * 1024);
+    expect(calculateBytes('25mB')).toBe(25 * 1024 * 1024);
+  });
+
+  it('converts a decimal with mb postfix', () => {
+    expect(calculateBytes('3.14mb')).toBe(3.14 * 1024 * 1024);
+    expect(calculateBytes('0.25MB')).toBe(0.25 * 1024 * 1024);
+    expect(calculateBytes('90.5Mb')).toBe(90.5 * 1024 * 1024);
+    expect(calculateBytes('25.0mB')).toBe(25 * 1024 * 1024);
+  });
+
+  it('converts an integer with gb postfix', () => {
+    expect(calculateBytes('0gb')).toBe(0);
+    expect(calculateBytes('5gb')).toBe(5 * 1024 * 1024 * 1024);
+    expect(calculateBytes('190GB')).toBe(190 * 1024 * 1024 * 1024);
+    expect(calculateBytes('92Gb')).toBe(92 * 1024 * 1024 * 1024);
+    expect(calculateBytes('25gB')).toBe(25 * 1024 * 1024 * 1024);
+  });
+
+  it('converts a decimal with gb postfix', () => {
+    expect(calculateBytes('3.14gb')).toBe(3.14 * 1024 * 1024 * 1024);
+    expect(calculateBytes('0.25GB')).toBe(0.25 * 1024 * 1024 * 1024);
+    expect(calculateBytes('90.5Gb')).toBe(90.5 * 1024 * 1024 * 1024);
+    expect(calculateBytes('25.0gB')).toBe(25 * 1024 * 1024 * 1024);
+  });
+
+  it ('converts a percentage with baseline', () => {
+    expect(calculateBytes('20%', '1mb')).toBe(1024 * 1024 * 1.2);
+    expect(calculateBytes('20%', '1mb', -1)).toBe(1024 * 1024 * 0.8);
+  });
+
+  it ('supports whitespace', () => {
+    expect(calculateBytes(' 5kb ')).toBe(5 * 1024);
+    expect(calculateBytes('0.25 MB')).toBe(0.25 * 1024 * 1024);
+    expect(calculateBytes(' 20 % ', ' 1 mb ')).toBe(1024 * 1024 * 1.2);
+  });
+});