# Idelta and counters

**URL:** <https://discuss.prometheus.io/t/idelta-and-counters/3152>\
**Category:** PromQL\
**Created:** [October 3, 2024, 2:01pm UTC](https://discuss.prometheus.io/t/idelta-and-counters/3152 "2024-10-03T14:01:58Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![shabba133](https://dub1.discourse-cdn.com/flex017/user_avatar/discuss.prometheus.io/shabba133/32/1057_2.png) [@shabba133](https://discuss.prometheus.io/u/shabba133)\
**Post date:** [October 3, 2024, 2:01pm UTC](https://discuss.prometheus.io/t/idelta-and-counters/3152/1 "2024-10-03T14:01:58Z")

</div>

Hi folks

There’s a throwaway line in the docs for idelta ([https://prometheus.io/docs/prometheus/latest/querying/functions/#idelta](https://prometheus.io/docs/prometheus/latest/querying/functions/#idelta)) which says…

> `idelta` should only be used with gauges.

My question is (and forgive me if this is naive) why, exactly? From playing around with it, it seems to do exactly what I want it do for a counter of mine. I haven’t observed any problems with it personally.

What problems can this actually cause?