diff --git a/Fusion/FusionCalibration.h b/Fusion/FusionCalibration.h
index 9193e04..733f572 100644
--- a/Fusion/FusionCalibration.h
+++ b/Fusion/FusionCalibration.h
@@ -35,7 +35,7 @@ static inline FusionVector FusionCalibrationInertial(const FusionVector uncalibr
  * @return Calibrated measurement.
  */
 static inline FusionVector FusionCalibrationMagnetic(const FusionVector uncalibrated, const FusionMatrix softIronMatrix, const FusionVector hardIronOffset) {
-    return FusionVectorSubtract(FusionMatrixMultiplyVector(softIronMatrix, uncalibrated), hardIronOffset);
+    return FusionMatrixMultiplyVector(softIronMatrix, FusionVectorSubtract(uncalibrated, hardIronOffset));
 }
 
 #endif
diff --git a/README.md b/README.md
index b9e85d0..2e6a655 100644
--- a/README.md
+++ b/README.md
@@ -101,7 +101,7 @@ i<sub>c</sub> = Ms(i<sub>u</sub> - b)
 
 The `FusionCalibrationMagnetic` function applies magnetometer calibration parameters using the calibration model:
 
-m<sub>c</sub> = Sm<sub>u</sub> - h
+m<sub>c</sub> = S(m<sub>u</sub> - h)
 
 - m<sub>c</sub> is the calibrated magnetometer measurement and `return` value
 - m<sub>u</sub> is the uncalibrated magnetometer measurement and `uncalibrated` argument