diff --git a/calculate.cpp b/calculate.cpp
new file mode 100644
index 0000000..f433751
--- /dev/null
+++ b/calculate.cpp
@@ -0,0 +1,48 @@
+#include "calculate.hpp"
+
+#include <limits>
+
+namespace phosphor::virtual_sensor
+{
+
+double calculateModifiedMedianValue(std::vector<double>& values)
+{
+    size_t size = values.size();
+    std::sort(values.begin(), values.end());
+    switch (size)
+    {
+        case 2:
+            /* Choose biggest value */
+            return values.at(1);
+        case 0:
+            return std::numeric_limits<double>::quiet_NaN();
+        default:
+            /* Choose median value */
+            if (size % 2 == 0)
+            {
+                // Average of the two middle values
+                return (values.at(size / 2) + values.at(size / 2 - 1)) / 2;
+            }
+            else
+            {
+                return values.at((size - 1) / 2);
+            }
+    }
+}
+
+double calculateMaximumValue(std::vector<double>& values)
+{
+    auto maxIt = std::max_element(values.begin(), values.end());
+    if (maxIt == values.end())
+    {
+        return std::numeric_limits<double>::quiet_NaN();
+    }
+    return *maxIt;
+}
+
+std::map<Interface, CalculationFunc> calculationIfaces{
+    {"xyz.openbmc_project.Configuration.Maximum", calculateMaximumValue},
+    {"xyz.openbmc_project.Configuration.ModifiedMedian",
+     calculateModifiedMedianValue}};
+
+} // namespace phosphor::virtual_sensor