There are several grade conversion systems that exist which can provide a good approximation to the German grading scale. One such system used by most universities is the modified bavarian formula. As per the study conducted by WES, the average grade in Germany is approximately around 3.0 and below WES table converts a 3.0 to a B equivalent in the US.
|90-100%||1.0–1.5||"sehr gut" (very good: an outstanding achievement)|
|80-90%||1.6–2.5||"gut" (good: an achievement substantially above average requirements)|
|65-80%||2.6–3.5||"befriedigend" (satisfactory: an achievement which corresponds to average requirements)|
|50-65%||3.6–4.0||"ausreichend" (sufficient: an achievement which barely meets the requirements)|
|0-50%||5.0||"mangelhaft" / "ungenügend" / "nicht bestanden" (insufficient / failed: an achievement which does not meet the requirements)|
Most colleges in India either use a 10 point scale known as the CGPA (Cumulative GPA), or just plain percentages. The 10 point scale can be either relative (as is the case with most of the elite colleges such as the IITs, NITs, and BITS Pilani), or absolute, in which case it would just be the percentage divided by 10.
Some colleges in India grade/score very stringently, since the min. percentage required to graduate is 50%. So, if you were an average student at a such a college, your CGPA/ Percentage would be 7.0 or 70%. Using above conversion table, your GPA on German scale would be 2.80. However, most elite German universities might straight-away thrash your application if your GPA is above 2.50 in German scale. This will not work; it’s like comparing Apples to Oranges, or German Apples with Indian Apples! This is why most schools don’t ask you to convert your score.