# Formulas in Logsatsh
**URL:** https://discuss.elastic.co/t/formulas-in-logsatsh/234650
**Category:** Logstash
**Created:** [May 28, 2020, 4:56am UTC](https://discuss.elastic.co/t/formulas-in-logsatsh/234650 "2020-05-28T04:56:29Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@katara](https://discuss.elastic.co/u/katara)
#### Post date: [May 28, 2020, 4:56am UTC](https://discuss.elastic.co/t/formulas-in-logsatsh/234650/1 "2020-05-28T04:56:29Z")
Hi,
I have a column in my source data which says if a ticket has met its SLAs.
met\_sla: true
or
met\_sla: false
I wanna calculate the below in Logstash and create a new field called target percent
Target= (count(met\_sal: true)/ count(met\_sla)) \*100
How do i do this?
Is this also possible in Kibana wit DSL queries?
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### Author:  [@Ranjith\_M](https://discuss.elastic.co/u/Ranjith_M)
#### Post date: [May 28, 2020, 5:46am UTC](https://discuss.elastic.co/t/formulas-in-logsatsh/234650/2 "2020-05-28T05:46:06Z")
@katara
If your question is building visualisation in kibana on the derived field, then the answer is No.
You can easily implement this using logstash ruby filter, and it will be efficient to do calculations during ingestion.
Check this link [https://www.elastic.co/guide/en/logstash/current/plugins-filters-ruby.html](https://www.elastic.co/guide/en/logstash/current/plugins-filters-ruby.html)
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### Author:  [@katara](https://discuss.elastic.co/u/katara)
#### Post date: [May 28, 2020, 5:48am UTC](https://discuss.elastic.co/t/formulas-in-logsatsh/234650/3 "2020-05-28T05:48:15Z")
@Ranjith_M, Would i also be able to collect count aggregations in ruby?
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### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [June 25, 2020, 5:48am UTC](https://discuss.elastic.co/t/formulas-in-logsatsh/234650/4 "2020-06-25T05:48:18Z")
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