diff --git a/aos/common/commonmath.h b/aos/common/commonmath.h
new file mode 100644
index 0000000..a77210f
--- /dev/null
+++ b/aos/common/commonmath.h
@@ -0,0 +1,18 @@
+#ifndef AOS_COMMON_MATH_H_
+#define AOS_COMMON_MATH_H_
+
+namespace aos {
+
+// Clips a value so that it is in [min, max]
+inline double Clip(double value, double min, double max) {
+  if (value > max) {
+    value = max;
+  } else if (value < min) {
+    value = min;
+  }
+  return value;
+}
+
+}  // namespace aos
+
+#endif  // AOS_COMMON_MATH_H_