diff --git a/tests/unit/spinner/spinner_methods.js b/tests/unit/spinner/spinner_methods.js
index 4f44a73aef1..41c991be304 100644
--- a/tests/unit/spinner/spinner_methods.js
+++ b/tests/unit/spinner/spinner_methods.js
@@ -73,6 +73,38 @@ test( "enable", function() {
 	equal( 2, element.val(), "keyboard - value changes on key UP" );
 });
 
+test( "isValid", function() {
+	expect( 8 );
+	var element = $( "#spin" ).spinner({
+			min: 0,
+			max: 10,
+			step: 2
+		}),
+		spinner = element.spinner( "instance" );
+	ok( !spinner.isValid(), "initial state is invalid" );
+
+	element.val( "this is not a number" );
+	ok( !spinner.isValid(), "text string is not valid" );
+
+	element.val( "0" );
+	ok( spinner.isValid(), "min value is valid" );
+
+	element.val( "10" );
+	ok( spinner.isValid(), "max value is valid" );
+
+	element.val( "4" );
+	ok( spinner.isValid(), "inbetween step is valid" );
+
+	element.val( "-1" );
+	ok( !spinner.isValid(), "below min is invalid" );
+
+	element.val( "11" );
+	ok( !spinner.isValid(), "above max is invalid" );
+
+	element.val( "1" );
+	ok( !spinner.isValid(), "step mismatch is invalid" );
+});
+
 test( "pageDown", function() {
 	expect( 4 );
 	var element = $( "#spin" ).val( -12 ).spinner({
diff --git a/ui/jquery.ui.spinner.js b/ui/jquery.ui.spinner.js
index c022413dc24..a4912fc7e75 100644
--- a/ui/jquery.ui.spinner.js
+++ b/ui/jquery.ui.spinner.js
@@ -418,6 +418,18 @@ $.widget( "ui.spinner", {
 		});
 	},
 
+	isValid: function() {
+		var value = this.value();
+
+		// null is invalid
+		if ( value === null ) {
+			return false;
+		}
+
+		// if value gets adjusted, it's invalid
+		return value === this._adjustValue( value );
+	},
+
 	// update the value without triggering change
 	_value: function( value, allowAny ) {
 		var parsed;