diff --git a/src/Coupons/Fixed.php b/src/Coupons/Fixed.php
index 8b25ef3..ad62c3e 100644
--- a/src/Coupons/Fixed.php
+++ b/src/Coupons/Fixed.php
@@ -43,12 +43,13 @@ public function __construct($code, $value, $options = [])
     public function discount($throwErrors = false)
     {
         $subTotal = app(LaraCart::SERVICE)->subTotal(false);
-        $total = $subTotal - $this->value;
 
         if (config('laracart.discountOnFees', false)) {
-            $total = $subTotal + app(LaraCart::SERVICE)->feeTotals(false) - $this->value;
+            $subTotal  = $subTotal + app(LaraCart::SERVICE)->feeTotals(false);
         }
 
+        $total = $subTotal - $this->value;
+
         if ($total < 0) {
             return $subTotal;
         }
diff --git a/src/Coupons/Percentage.php b/src/Coupons/Percentage.php
index d25ee29..1ba5327 100644
--- a/src/Coupons/Percentage.php
+++ b/src/Coupons/Percentage.php
@@ -4,6 +4,7 @@
 
 use LukePOLO\LaraCart\CartItem;
 use LukePOLO\LaraCart\Contracts\CouponContract;
+use LukePOLO\LaraCart\Exceptions\CouponException;
 use LukePOLO\LaraCart\LaraCart;
 use LukePOLO\LaraCart\Traits\CouponTrait;
 
@@ -27,10 +28,14 @@ class Percentage implements CouponContract
      * @param $code
      * @param $value
      * @param array $options
+     * @throws \Exception
      */
     public function __construct($code, $value, $options = [])
     {
         $this->code = $code;
+        if($value > 1) {
+            throw new CouponException('Invalid value for a percentage coupon. The value must be between 0 and 1.');
+        }
         $this->value = $value;
 
         $this->setOptions($options);
@@ -62,8 +67,13 @@ public function forItem(CartItem $item)
      */
     public function discount($throwErrors = false)
     {
+        $subTotal = app(LaraCart::SERVICE)->subTotal(false);
+        if (config('laracart.discountOnFees', false)) {
+            $subTotal = $subTotal + app(LaraCart::SERVICE)->feeTotals(false);
+        }
+
         return LaraCart::formatMoney(
-            app(LaraCart::SERVICE)->subTotal(false) * $this->value,
+            $subTotal * $this->value,
             null,
             null,
             false
diff --git a/tests/CouponsTest.php b/tests/CouponsTest.php
index ba7fd3c..454b1cd 100644
--- a/tests/CouponsTest.php
+++ b/tests/CouponsTest.php
@@ -16,8 +16,17 @@ public function testAddPercentageCoupon()
     {
         $this->addItem(3, 1);
 
+        try {
+            $percentCoupon = new LukePOLO\LaraCart\Coupons\Percentage('10%OFF', '23');
+            $this->setExpectedException(\LukePOLO\LaraCart\Exceptions\CouponException::class);
+        } catch (\LukePOLO\LaraCart\Exceptions\CouponException $e) {
+            $this->assertEquals('Invalid value for a percentage coupon. The value must be between 0 and 1.', $e->getMessage());
+        }
+
         $percentCoupon = new LukePOLO\LaraCart\Coupons\Percentage('10%OFF', '.1');
 
+
+
         $this->laracart->addCoupon($percentCoupon);
 
         $this->assertEquals($percentCoupon, $this->laracart->findCoupon('10%OFF'));
@@ -426,5 +435,13 @@ public function testFixedCouponWithFeeWithTotalLessThanCoupon()
         $this->app['config']->set('laracart.discountOnFees', true);
 
         $this->assertEquals('500', $fixedCoupon->discount());
+
+
+        $this->app['config']->set('laracart.discountOnFees', true);
+
+        $percentCoupon = new LukePOLO\LaraCart\Coupons\Percentage('100% Off', 1);
+        $this->laracart->addCoupon($percentCoupon);
+
+        $this->assertEquals(0, $this->laracart->total(false));
     }
 }