diff --git a/5_Currency_Calculator/Currency_Calculator.c b/5_Currency_Calculator/Currency_Calculator.c
index 24ab015..5cceb4f 100644
--- a/5_Currency_Calculator/Currency_Calculator.c
+++ b/5_Currency_Calculator/Currency_Calculator.c
@@ -1,4 +1,5 @@
 #include <stdio.h>
+#include <math.h>
 
 int main() {
     // variables
@@ -13,6 +14,12 @@ int main() {
     printf("\n1 EUR\n2 USD\n3 JPY\n\nPlease type in the target currency: ");
     scanf("%i", &targetCurrency);
 
+    // check for valid input
+    if (currentCurrency < 1 || currentCurrency > 4 || targetCurrency < 1 || targetCurrency > 4) {
+        printf("Invalid currencies.");
+        return 1;
+    }
+
     // calculating
     if (currentCurrency != targetCurrency) {
         // converting to base currency
@@ -39,6 +46,9 @@ int main() {
         }
     }
 
+    // rounding fun
+    amount = round((amount*100))/100;
+
     // output
     printf("Amount in target currency is: %lf", amount);