diff --git a/README.md b/README.md
index e1278f2..54b378e 100644
--- a/README.md
+++ b/README.md
@@ -91,7 +91,7 @@ ReactDOM.render(<div>
 		  <td>strokeLinecap</td>
 		  <td>String</td>
 		  <td>'round'</td>
-		  <td>The shape to be used at the end of the progress bar, can be `square` or `round`.</td>
+		  <td>The shape to be used at the end of the progress bar, can be `butt`, `square` or `round`.</td>
 		</tr>
     <tr>
       <td>prefixCls</td>
diff --git a/src/types.js b/src/types.js
index d1fd5a2..4a44dcc 100644
--- a/src/types.js
+++ b/src/types.js
@@ -17,7 +17,7 @@ export const propTypes = {
   percent: PropTypes.oneOfType([PropTypes.number, PropTypes.string]),
   prefixCls: PropTypes.string,
   strokeColor: PropTypes.string,
-  strokeLinecap: PropTypes.oneOf(['round', 'square']),
+  strokeLinecap: PropTypes.oneOf(['butt', 'round', 'square']),
   strokeWidth: PropTypes.oneOfType([PropTypes.number, PropTypes.string]),
   style: PropTypes.object,
   trailColor: PropTypes.string,