diff --git a/include/utils.hpp b/include/utils.hpp
index c8d3e4a..5c2926f 100644
--- a/include/utils.hpp
+++ b/include/utils.hpp
@@ -35,6 +35,8 @@
     #define DEBUG(msg)
 #endif
 
+#define ASSERT(expr) m_assert(expr, #expr, __FUNCTION__, __FILE__, __LINE__)
+
 /** 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
  *  Source: https://github.com/anderkve/FYS3150/blob/master/code_examples/compilation_linking/example_1/src/utils.cpp
@@ -62,4 +64,6 @@ 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);
+
 #endif
diff --git a/src/utils.cpp b/src/utils.cpp
index 0e93a31..3c35a9d 100644
--- a/src/utils.cpp
+++ b/src/utils.cpp
@@ -10,6 +10,8 @@
  *  @bug No known bugs
  * */
 #include "utils.hpp"
+#include <cstdlib>
+#include <string>
 
 std::string scientific_format(double d, int width, int prec)
 {
@@ -26,3 +28,20 @@ std::string scientific_format(const std::vector<double>& v, int width, int prec)
     }
     return ss.str();
 }
+
+void m_assert(bool expr, 
+              const char* expr_str, 
+              const char* f, 
+              const char* file, 
+              int line)
+{
+    printf("%s: ", f);
+    if (expr) {
+        printf("\x1B[32mOK\033[0m\n\n");
+    }
+    else {
+        printf("\x1B[31mFAIL\033[0m\n\n");
+        printf("%s %d: Assertion (%s) Failed\n\n", file, line, expr_str);
+        abort();
+    }
+}