diff --git a/api/sum().js b/api/sum().js
index 0f41709..91b994c 100644
--- a/api/sum().js
+++ b/api/sum().js
@@ -3,6 +3,14 @@
  * and sum it, returning the summed value. The data can come from any data
  * source, including column data, cells or rows.
  *
+ * Note that it will attempt to 'deformat' any string based data that is passed
+ * into it - i.e. it will strip any non-numeric characters in order to make a
+ * best effort attempt to sum all data types. This can be useful when working
+ * with formatting numbers such as currency. However the trade-off is that no
+ * error is thrown if non-numeric data is passed in. You should be aware of this
+ * in case unexpected values are returned - likely the input data is not what is
+ * expected.
+ *
  *  @name sum()
  *  @summary Sum the values in a data set.
  *  @author [Allan Jardine](http://sprymedia.co.uk)
@@ -28,9 +36,16 @@
  *    } );
  */
 
-jQuery.fn.dataTable.Api.register( 'sum()', function () {
+jQuery.fn.dataTable.Api.register( 'sum()', function ( ) {
 	return this.flatten().reduce( function ( a, b ) {
-		return (a*1) + (b*1); // cast values in-case they are strings
+		if ( typeof a === 'string' ) {
+			a = a.replace(/[^\d.-]/g, '') * 1;
+		}
+		if ( typeof b === 'string' ) {
+			b = b.replace(/[^\d.-]/g, '') * 1;
+		}
+
+		return a + b;
 	}, 0 );
 } );