Estimating Euler's Constant, $e$

Given the desired depth of calculation

This calculator estimates Euler's Constant, e to the requested precision. It uses the following formula:

To use the calculator simply enter the depth of the calculation (the number of terms utilized). The display shows the result and the difference from $e$ as defined by javascript's Math.E. Below $e$ is shown calculated to 50 places.

2.718 281 828 459 045 235 360 287 471 352 662 497 757 247 093 699 96

I can only show $e$ to 21 numerals of precision as that is the limit of the Number.precision() function and ultimately the limit of 64-bit computing.