diff --git a/libraries/AP_SerialManager/AP_SerialManager.cpp b/libraries/AP_SerialManager/AP_SerialManager.cpp
index 306a31a916..4bf70cd728 100644
--- a/libraries/AP_SerialManager/AP_SerialManager.cpp
+++ b/libraries/AP_SerialManager/AP_SerialManager.cpp
@@ -245,3 +245,43 @@ void AP_SerialManager::set_console_baud(enum SerialProtocol protocol) const
         }
     }
 }
+
+/*
+ *  map from a 16 bit EEPROM baud rate to a real baud rate
+ * The practical rates for APM1/APM2 are up to 500kbaud, although
+ * beyond 115200 isn't recommended. For PX4 we can do 1.5MBit,
+ * although 921600 is more reliable
+ */
+uint32_t AP_SerialManager::map_baudrate(int32_t rate) const
+{
+    if (rate <= 0) {
+        rate = 57;
+    }
+    switch (rate) {
+    case 1:    return 1200;
+    case 2:    return 2400;
+    case 4:    return 4800;
+    case 9:    return 9600;
+    case 19:   return 19200;
+    case 38:   return 38400;
+    case 57:   return 57600;
+    case 100:  return 100000;
+    case 111:  return 111100;
+    case 115:  return 115200;
+    case 230:  return 230400;
+    case 460:  return 460800;
+    case 500:  return 500000;
+    case 921:  return 921600;
+    case 1500:  return 1500000;
+    }
+
+    if (rate > 2000) {
+        // assume it is a direct baudrate. This allows for users to
+        // set an exact baudrate as long as it is over 2000 baud
+        return (uint32_t)rate;
+    }
+
+    // otherwise allow any other kbaud rate
+    return rate*1000;
+}
+
diff --git a/libraries/AP_SerialManager/AP_SerialManager.h b/libraries/AP_SerialManager/AP_SerialManager.h
index 3eb309f0db..c9d48aabf5 100644
--- a/libraries/AP_SerialManager/AP_SerialManager.h
+++ b/libraries/AP_SerialManager/AP_SerialManager.h
@@ -120,6 +120,8 @@ private:
 
     // array of uart info
     serial_state state[SERIALMANAGER_NUM_PORTS];
+
+    uint32_t map_baudrate(int32_t rate) const;
 };
 
 #endif // _AP_SERIALMANAGER_