diff --git a/src/PriceFormatter.php b/src/PriceFormatter.php
index de243cc..2bff95b 100644
--- a/src/PriceFormatter.php
+++ b/src/PriceFormatter.php
@@ -35,6 +35,10 @@ class PriceFormatter
 
         $removeNonDigits = preg_replace('/[^\d'.preg_quote($currency->decimalSeparator()).']/', '', $formatted);
 
+        if (!is_string($removeNonDigits)) {
+            throw new \Exception('The formatted string could not be resolved to a valid number.');
+        }
+
         return (float) str_replace($currency->decimalSeparator(), '.', $removeNonDigits);
     }
 }