# Adding fields

**URL:** https://discuss.elastic.co/t/adding-fields/36891
**Category:** Logstash
**Created:** [December 10, 2015, 3:28pm UTC](https://discuss.elastic.co/t/adding-fields/36891 "2015-12-10T15:28:35Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![marcmga](https://avatars.discourse-cdn.com/v4/letter/m/3bc359/32.png) [@marcmga](https://discuss.elastic.co/u/marcmga)
#### Post date: [December 10, 2015, 3:28pm UTC](https://discuss.elastic.co/t/adding-fields/36891/1 "2015-12-10T15:28:35Z")

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Hello there,

I want to know if there's a way to add two or more fields. We take two fields which are numbers (not string) and want to add each other into another field.  
Or even more, is there a way to add a number to a field? Imagine i receive a log with a field containing a number, may i add "10" to that field?

Thanks

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### Author: ![magnusbaeck](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/magnusbaeck/32/44943_2.png) [@magnusbaeck](https://discuss.elastic.co/u/magnusbaeck)
#### Post date: [December 10, 2015, 3:36pm UTC](https://discuss.elastic.co/t/adding-fields/36891/2 "2015-12-10T15:36:04Z")

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I don't think there are any general filters for performing field arithmetics, but you can always use a ruby filter.

```auto
filter {
  ruby {
    code => "event['sum'] = event['number_field_1'] + event['number_field_2']"
  }
}

```

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### Author: ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)
#### Post date: [July 6, 2017, 5:19am UTC](https://discuss.elastic.co/t/adding-fields/36891/3 "2017-07-06T05:19:03Z")

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