diff --git a/software/firmware/energy-montior/README.md b/software/firmware/energy-montior/README.md
index 68ea45f..aa4c6a5 100644
--- a/software/firmware/energy-montior/README.md
+++ b/software/firmware/energy-montior/README.md
@@ -76,7 +76,7 @@ The only interesting part is this line:
   emon1.current(current1Pin, 8);  // Pin and Calibration
 ```
 
-The calibration value "8" was done with a Fluke multimeter (and maybe a not so ideal burden resistor).
+The [calibration](https://docs.openenergymonitor.org/electricity-monitoring/ctac/calibration.html) value "8" was done with a Fluke multimeter (and maybe a not so ideal burden resistor).
 
 The code just prints the current power consumption to serial out: