# Logarithmic operation in Kibana

**URL:** <https://discuss.elastic.co/t/logarithmic-operation-in-kibana/219027>\
**Category:** Kibana\
**Created:** [February 12, 2020, 3:25pm UTC](https://discuss.elastic.co/t/logarithmic-operation-in-kibana/219027 "2020-02-12T15:25:43Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![flash1293](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/flash1293/32/41227_2.png) [@flash1293](https://discuss.elastic.co/u/flash1293)\
**Post date:** [February 12, 2020, 4:34pm UTC](https://discuss.elastic.co/t/logarithmic-operation-in-kibana/219027/2 "2020-02-12T16:34:39Z")

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You can't do this in regular visualizations, but it's possible in canvas due to the flexibility of the expression language. After fetching the dBm data using an Elasticsearch SQL query, you can pipe it through a math expression built using a second Elasticsearch SQL query fetching the global average.

Same approach as in this answer [Calculating purcentage in a metric](https://discuss.elastic.co/t/calculating-purcentage-in-a-metric/211652/2)

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