gives the number of decimal digits of precision used for machine‐precision numbers.


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

- A typical value of $MachinePrecision is 53Log[10,2] or approximately 16.
- $MachinePrecision is the numerical value of MachinePrecision.
Examples
open all close allScope (1)
Applications (1)
Properties & Relations (3)
$MachinePrecision evaluates to a number while MachinePrecision is a numerical constant:
$MachinePrecision is numerically Equal to MachinePrecision:
$MachinePrecision is the machine precision approximation to MachinePrecision:
Numbers with just a few digits entered are assumed to have machine precision:
Precision is based on the number of digits when more than ⌈$MachinePrecision⌉+1 are entered:
$MachinePrecision times the number of bits per digit gives the binary machine precision:
Possible Issues (1)
$MachinePrecision uses arbitrary precision computations with machine precision resolution:
MachinePrecision uses machine number computations:
Tech Notes
Related Guides
History
Introduced in 1991 (2.0) | Updated in 2003 (5.0)
Text
Wolfram Research (1991), $MachinePrecision, Wolfram Language function, https://reference.wolfram.com/language/ref/$MachinePrecision.html (updated 2003).
CMS
Wolfram Language. 1991. "$MachinePrecision." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2003. https://reference.wolfram.com/language/ref/$MachinePrecision.html.
APA
Wolfram Language. (1991). $MachinePrecision. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/$MachinePrecision.html
BibTeX
@misc{reference.wolfram_2025_$machineprecision, author="Wolfram Research", title="{$MachinePrecision}", year="2003", howpublished="\url{https://reference.wolfram.com/language/ref/$MachinePrecision.html}", note=[Accessed: 08-August-2025]}
BibLaTeX
@online{reference.wolfram_2025_$machineprecision, organization={Wolfram Research}, title={$MachinePrecision}, year={2003}, url={https://reference.wolfram.com/language/ref/$MachinePrecision.html}, note=[Accessed: 08-August-2025]}