Most 19^th and some early 20^th century coins used Saka Era (SE) dates.

To convert: SE date + 78 = AD date.

SE date = 1793. AD date = 1793 + 78 = 1871.

Some 19^th and most 20^th century coins to the present use Vikram Samvat era (VS) dates.
To convert: VS date – 57 = AD date

Example 1:

VS date = 2036. AD date = 2036 – 57 = 1979.

Example 2:

VS date = 2058. AD date = 2058 – 57 = 2001.