# Mathemathical Operation on Date or Timestamp
**URL:** https://discuss.elastic.co/t/mathemathical-operation-on-date-or-timestamp/51334
**Category:** Logstash
**Created:** [May 30, 2016, 2:58pm UTC](https://discuss.elastic.co/t/mathemathical-operation-on-date-or-timestamp/51334 "2016-05-30T14:58:09Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@sombilat](https://discuss.elastic.co/u/sombilat)
#### Post date: [May 30, 2016, 2:58pm UTC](https://discuss.elastic.co/t/mathemathical-operation-on-date-or-timestamp/51334/1 "2016-05-30T14:58:09Z")
Hello,
I want to perform a Mathemathical operation on a date field.
I am getting a timestamp field like so:
add\_field =\> ["received\_at", "%{@timestamp}"]
Now, I will create a seperate field with a Date before the received\_at field.
add\_field =\> ["received\_from", "%{@timestamp} - 1"]
Is there a way to do like, a Minus 1 day from the field?
Or do you have a suggestion on how I manipulate this?
Thanks,
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### Author:  [@magnusbaeck](https://discuss.elastic.co/u/magnusbaeck)
#### Post date: [May 31, 2016, 7:47am UTC](https://discuss.elastic.co/t/mathemathical-operation-on-date-or-timestamp/51334/2 "2016-05-31T07:47:08Z")
You'll have to use a ruby filter for this. Internally the `@timestamp` value has a date/time data type that allows date/time arithmetic so it should be simple to subtract a day.
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### Author:  [@sombilat](https://discuss.elastic.co/u/sombilat)
#### Post date: [May 31, 2016, 11:57am UTC](https://discuss.elastic.co/t/mathemathical-operation-on-date-or-timestamp/51334/3 "2016-05-31T11:57:28Z")
Thanks Magnus! 😃
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### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [July 6, 2017, 4:55am UTC](https://discuss.elastic.co/t/mathemathical-operation-on-date-or-timestamp/51334/4 "2017-07-06T04:55:15Z")