diff --git a/ios/Utils/RNSVGPercentageConverter.m b/ios/Utils/RNSVGPercentageConverter.m
index 62c9b3aa..5d3e5815 100644
--- a/ios/Utils/RNSVGPercentageConverter.m
+++ b/ios/Utils/RNSVGPercentageConverter.m
@@ -47,6 +47,9 @@ static NSRegularExpression* percentageRegExp;
 
 + (BOOL)isPercentage:(NSString *) string
 {
+    if (![string isKindOfClass:[NSString class]]) {
+      return NO;
+    }
     return [percentageRegExp firstMatchInString:string options:0 range:NSMakeRange(0, [string length])] != nil;
 }