# How to transform the unit of tally？

**URL:** <https://openmc.discourse.group/t/how-to-transform-the-unit-of-tally/580>\
**Category:** User Support\
**Created:** [March 19, 2020, 1:19pm UTC](https://openmc.discourse.group/t/how-to-transform-the-unit-of-tally/580 "2020-03-19T13:19:03Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Bin\_Deng](https://avatars.discourse-cdn.com/v4/letter/b/d26b3c/32.png) [@Bin\_Deng](https://openmc.discourse.group/u/Bin_Deng)\
**Post date:** [March 19, 2020, 1:19pm UTC](https://openmc.discourse.group/t/how-to-transform-the-unit-of-tally/580/1 "2020-03-19T13:19:03Z")

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Hi all,  
There are some specifications of tally in openmc user’s guide. For example, the “flux” tally has the unit of “neutron-cm per source particle”. However, the correct unit of “flux” is neutron/(m-2_s-1). So, how to transform the unit of tally so that we can get the real “flux”？  
Similarly, how can we get the total neutron production rate: \< mu_sigma\*phi \>

Best regards  
Benjamin

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**Author:** ![Javier\_Gonzalez](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/javier_gonzalez/32/1095_2.png) [@Javier\_Gonzalez](https://openmc.discourse.group/u/Javier_Gonzalez)\
**Post date:** [March 20, 2020, 3:52pm UTC](https://openmc.discourse.group/t/how-to-transform-the-unit-of-tally/580/2 "2020-03-20T15:52:00Z")

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Hi Benjamin,

Details about how to do the units transformation are [here](https://groups.google.com/forum/#!msg/openmc-users/r5JtjyH9BIM/nGM-MPfcAgAJ).

Javier