The EFIT application was created by a diabetic for diabetics.
Its operation is very simple:

When using for the first time, fill in your glucose targets, your Ratio(s), your insulin sensitivity. You have three additional parameters to reduce your bolus by a certain percentage during physical activity after the meal.

These values ​​can be modified as desired.

It is strongly advised to inform the values ​​transmitted by your diabetologist. To calculate the bolus insulin, provide your blood sugar as well as the number of carbohydrates.

Choose physical activity: no activity, low activity, moderate activity, intense activity.

Finally click on "calculate"

EFIT takes into account all the parameters to calculate the suggested insulin bolus.