diff --git a/js/mapbox-gl.js b/js/mapbox-gl.js
index 13390003642..7b4ee6a839a 100644
--- a/js/mapbox-gl.js
+++ b/js/mapbox-gl.js
@@ -6,8 +6,7 @@ const browser = require('./util/browser');
 const mapboxgl = module.exports = {};
 
 mapboxgl.version = require('../package.json').version;
-mapboxgl.workerCount = Math.max(browser.hardwareConcurrency - 1, 1);
-
+mapboxgl.workerCount = Math.max(Math.floor(Math.log(browser.hardwareConcurrency) / Math.LN2), 1);
 
 mapboxgl.Map = require('./ui/map');
 mapboxgl.Control = require('./ui/control/control');
diff --git a/test/js/mapbox-gl.js b/test/js/mapbox-gl.js
index c79571a5d05..a83885f202f 100644
--- a/test/js/mapbox-gl.js
+++ b/test/js/mapbox-gl.js
@@ -1,7 +1,6 @@
 'use strict';
 
 const test = require('mapbox-gl-js-test').test;
-const proxyquire = require('proxyquire');
 const mapboxgl = require('../../js/mapbox-gl');
 
 test('mapboxgl', (t) => {
@@ -10,11 +9,8 @@ test('mapboxgl', (t) => {
         t.end();
     });
 
-    t.test('.workerCount defaults to hardwareConcurrency - 1', (t) => {
-        const mapboxgl = proxyquire('../../js/mapbox-gl', {
-            './util/browser': { hardwareConcurrency: 15 }
-        });
-        t.equal(mapboxgl.workerCount, 14);
+    t.test('workerCount', (t) => {
+        t.ok(typeof mapboxgl.workerCount === 'number');
         t.end();
     });
     t.end();