Built-in Mathematica Symbol

$MachinePrecision

$MachinePrecision
gives the number of decimal digits of precision used for machine-precision numbers.

Hardware machine precision used for floating point computation:

Machine number approximating

:

Arbitrary precision number approximating

with the same precision as machine numbers:

Make sure computations are carried out with the same precision as machine numbers:

Without fixing the precision, the resulting precision may be lower:

$MachinePrecision evaluates to a number while MachinePrecision is a numerical constant:

$MachinePrecision is numerically Equal to MachinePrecision:

$MachinePrecision is the machine precision approximation to MachinePrecision:

Numbers with just a few digits entered are assumed to have machine precision:

Precision is based on the number of digits when more than

are entered:

$MachinePrecision times the number of bits per digit gives the binary machine precision:

$MachinePrecision uses arbitrary precision computations with machine precision resolution:

MachinePrecision uses machine number computations: