# Calculate time

**URL:** https://community.homey.app/t/calculate-time/148641
**Category:** Questions & Help
**Created:** [January 5, 2026, 11:01pm UTC](https://community.homey.app/t/calculate-time/148641 "2026-01-05T23:01:39Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![Jonas](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/jonas/32/123371_2.png) [@Jonas](https://community.homey.app/u/Jonas)
#### Post date: [January 5, 2026, 11:01pm UTC](https://community.homey.app/t/calculate-time/148641/1 "2026-01-05T23:01:39Z")

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Hi,

I’m trying to find a way to do this without making a script but I don’t really know how. I tried with BBL but I can’t wrap my head around how it works.

I have a time in hh:mm format in a text variable. I want to subtract 3 hours from that.

It’s there any simple way of doing this?

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### Author: ![Rmb](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/rmb/32/79135_2.png) [@Rmb](https://community.homey.app/u/Rmb)
#### Post date: [January 6, 2026, 5:28am UTC](https://community.homey.app/t/calculate-time/148641/2 "2026-01-06T05:28:47Z")

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Convert the time to Epoche time, substract the number of milliseconds that equals 3 hours, and convert it back to normal time.

Search this forum for Epoche.