diff --git a/src/decbinary.c b/src/decbinary.c
new file mode 100644
index 0000000..fcf1b3b
--- /dev/null
+++ b/src/decbinary.c
@@ -0,0 +1,17 @@
+#include <stdio.h>
+#include "decbinary.h"
+
+int decimal_to_binary(int dezimalzahl) {
+
+
+    int binärzahl[32];
+    int i = 0;
+
+    while (dezimalzahl > 0) {
+        binärzahl[i++] = dezimalzahl % 2;
+        dezimalzahl /= 2;
+    }
+
+    return i;
+}
+
diff --git a/src/decbinary.h b/src/decbinary.h
new file mode 100644
index 0000000..7c5b5ff
--- /dev/null
+++ b/src/decbinary.h
@@ -0,0 +1,8 @@
+
+#ifndef LINKES_TWIX_DECBINARY_H
+#define LINKES_TWIX_DECBINARY_H
+
+int decimal_to_binary(int dezimalzahl);
+
+
+#endif //LINKES_TWIX_DECBINARY_H
diff --git a/src/test_decbinary.c b/src/test_decbinary.c
new file mode 100644
index 0000000..747220c
--- /dev/null
+++ b/src/test_decbinary.c
@@ -0,0 +1,18 @@
+#ifdef TEST
+
+#include "decbinary.h"
+#include "unity.h"
+
+void setUp(void)
+{
+}
+
+void test_decimal_1(void)
+{
+    int result, expected = 10;
+    result = decimal_to_binary(2);
+
+    TEST_ASSERT_EQUAL_INT(expected, result);
+}
+
+#endif //TEST
\ No newline at end of file