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$ProcessorCount

gives the number of processor cores available on the computer system on which the Wolfram System is being run.

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$ProcessorCount

$ProcessorCount

gives the number of processor cores available on the computer system on which the Wolfram System is being run.

Details

Examples

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Basic Examples  (1)

Wolfram Language code: $ProcessorCount

Applications  (2)

By default, as many parallel kernels are launched as there are processor cores:

Wolfram Language code: $ProcessorCount
Wolfram Language code: $ConfiguredKernels
Wolfram Language code: LaunchKernels[]

You can change $ProcessorCount in a new session to simulate a multicore computer:

Wolfram Language code: Unprotect[$ProcessorCount];$ProcessorCount = 8;
Wolfram Language code: LaunchKernels[]

Possible Issues  (2)

No kernels are launched by default on a single-core computer:

Wolfram Language code: $ProcessorCount
Wolfram Language code: LaunchKernels[]

Specify the number of desired kernels to launch them anyway:

Wolfram Language code: LaunchKernels[2]

Changing $ProcessorCount takes effect only if it happens before using any parallel commands:

Wolfram Language code: $ProcessorCount
Wolfram Language code: $KernelCount
Wolfram Language code: Unprotect[$ProcessorCount];$ProcessorCount = 8;
Wolfram Language code: Length[LaunchKernels[]]

You can always launch the desired number of kernels explicitly:

Wolfram Language code: Length[LaunchKernels[8]]
Wolfram Research (2008), $ProcessorCount, Wolfram Language function, https://reference.wolfram.com/language/ref/$ProcessorCount.html.

Text

Wolfram Research (2008), $ProcessorCount, Wolfram Language function, https://reference.wolfram.com/language/ref/$ProcessorCount.html.

CMS

Wolfram Language. 2008. "$ProcessorCount." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/$ProcessorCount.html.

APA

Wolfram Language. (2008). $ProcessorCount. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/$ProcessorCount.html

BibTeX

@misc{reference.wolfram_2026_$processorcount, author="Wolfram Research", title="{$ProcessorCount}", year="2008", howpublished="\url{https://reference.wolfram.com/language/ref/$ProcessorCount.html}", note=[Accessed: 12-June-2026]}

BibLaTeX

@online{reference.wolfram_2026_$processorcount, organization={Wolfram Research}, title={$ProcessorCount}, year={2008}, url={https://reference.wolfram.com/language/ref/$ProcessorCount.html}, note=[Accessed: 12-June-2026]}