diff --git a/include/utils.hpp b/include/utils.hpp
index 5c2926f..a41ce7b 100644
--- a/include/utils.hpp
+++ b/include/utils.hpp
@@ -23,7 +23,7 @@
 /** @def DEBUG(msg)
  *  @brief Writes a debug message
  *
- *  This function writes a debug message that includes the filename,
+ *  This macro writes a debug message that includes the filename,
  *  line number, and a custom message. The function is wrapped in an ifdef
  *  that checks if DBG is defined, so one can choose to display the debug 
  *  messages by adding the -DDBG flag when compiling.
@@ -35,7 +35,14 @@
     #define DEBUG(msg)
 #endif
 
-#define ASSERT(expr) m_assert(expr, #expr, __FUNCTION__, __FILE__, __LINE__)
+/** @def ASSERT(expr)
+ *  @brief A prettier assertion function.
+ *
+ *  This macro calls the m_assert function which is a more informative
+ *  assertion function than the regular assert function from cassert.
+ * */
+#define ASSERT(expr, msg) m_assert(expr, #expr, __FUNCTION__, __FILE__, \
+                                   __LINE__, msg)
 
 /** Code stolen from https://github.com/anderkve/FYS3150
  *  Header: https://github.com/anderkve/FYS3150/blob/master/code_examples/compilation_linking/example_1/include/utils.hpp
@@ -64,6 +71,23 @@ std::string scientific_format(const std::vector<double>& v,
                               int width=20, 
                               int prec=10);
 
-void m_assert(bool expr, const char* expr_str, const char* func, const char* file, int line);
+/** @brief Test an expression, confirm that test is ok, or abort execution.
+ *
+ *  This function takes in an expression and prints an OK message if it's
+ *  true, or it prints a fail message and aborts execution if it fails.
+ *
+ *  @param expr The expression to be evaluated
+ *  @param expr_str The stringified version of the expression
+ *  @param func The function name of the caller
+ *  @param file The file of the caller
+ *  @param line The line number where this function is called from
+ *  @param msg The message to be displayed
+ * */
+void m_assert(bool expr, 
+              const char* expr_str, 
+              const char* func, 
+              const char* file, 
+              int line,
+              const char* msg);
 
 #endif
diff --git a/src/utils.cpp b/src/utils.cpp
index 3c35a9d..f326b19 100644
--- a/src/utils.cpp
+++ b/src/utils.cpp
@@ -11,7 +11,9 @@
  * */
 #include "utils.hpp"
 #include <cstdlib>
+#include <cstring>
 #include <string>
+#include <bits/stdc++.h>
 
 std::string scientific_format(double d, int width, int prec)
 {
@@ -29,19 +31,35 @@ std::string scientific_format(const std::vector<double>& v, int width, int prec)
     return ss.str();
 }
 
+static void print_message(const char* msg)
+{
+    if (strlen(msg) > 0) {
+        std::cout << "message: " << msg << "\n\n";
+    }
+    else {
+        std::cout << "\n";
+    }
+}
+
 void m_assert(bool expr, 
               const char* expr_str, 
               const char* f, 
               const char* file, 
-              int line)
+              int line,
+              const char* msg)
 {
-    printf("%s: ", f);
+    std::string new_assert(strlen(f) + (expr ? 4 : 6), '-');
+    std::cout << "\x1B[36m" << new_assert << "\033[0m\n";
+    std::cout << f << ": ";
     if (expr) {
-        printf("\x1B[32mOK\033[0m\n\n");
+        std::cout << "\x1B[32mOK\033[0m\n";
+        print_message(msg);
     }
     else {
-        printf("\x1B[31mFAIL\033[0m\n\n");
-        printf("%s %d: Assertion (%s) Failed\n\n", file, line, expr_str);
+        std::cout << "\x1B[31mFAIL\033[0m\n";
+        print_message(msg);
+        std::cout << file <<  " " <<  line << ": Assertion \"" 
+            << expr_str << "\" Failed\n\n";
         abort();
     }
 }