diff --git a/__tests__/fixtures/tailwind-output-important.css b/__tests__/fixtures/tailwind-output-important.css
index d684b24dea96..c23f8657fb04 100644
--- a/__tests__/fixtures/tailwind-output-important.css
+++ b/__tests__/fixtures/tailwind-output-important.css
@@ -545,9 +545,9 @@ samp {
   width: 100%;
 }
 
-@media (min-width: 568px) {
+@media (min-width: 640px) {
   .container {
-    max-width: 568px;
+    max-width: 640px;
   }
 }
 
@@ -6601,7 +6601,7 @@ samp {
   color: #e3342f;
 }
 
-@media (min-width: 568px) {
+@media (min-width: 640px) {
   .sm\:list-reset {
     list-style: none !important;
     padding: 0 !important;
diff --git a/__tests__/fixtures/tailwind-output-with-explicit-screen-utilities.css b/__tests__/fixtures/tailwind-output-with-explicit-screen-utilities.css
index 2a7a723523d8..375ae1e7ae33 100644
--- a/__tests__/fixtures/tailwind-output-with-explicit-screen-utilities.css
+++ b/__tests__/fixtures/tailwind-output-with-explicit-screen-utilities.css
@@ -2,7 +2,7 @@
   color: red;
 }
 
-@media (min-width: 568px) {
+@media (min-width: 640px) {
   .sm\:example {
     color: red;
   }
diff --git a/__tests__/fixtures/tailwind-output.css b/__tests__/fixtures/tailwind-output.css
index 1bf1e39d5ceb..d8b5cdfc0fbe 100644
--- a/__tests__/fixtures/tailwind-output.css
+++ b/__tests__/fixtures/tailwind-output.css
@@ -545,9 +545,9 @@ samp {
   width: 100%;
 }
 
-@media (min-width: 568px) {
+@media (min-width: 640px) {
   .container {
-    max-width: 568px;
+    max-width: 640px;
   }
 }
 
@@ -6601,7 +6601,7 @@ samp {
   color: #e3342f;
 }
 
-@media (min-width: 568px) {
+@media (min-width: 640px) {
   .sm\:list-reset {
     list-style: none;
     padding: 0;
diff --git a/defaultTheme.js b/defaultTheme.js
index 17e1c6e6aad5..2d35ec952a67 100644
--- a/defaultTheme.js
+++ b/defaultTheme.js
@@ -107,7 +107,7 @@ module.exports = function() {
       '64': '16rem',
     },
     screens: {
-      sm: '568px',
+      sm: '640px',
       md: '768px',
       lg: '1024px',
       xl: '1280px',