Milestone & Deadline - Sync Two Timeline Columns

Hi - I have tried searching for this but not finding anything.

I need to set both deadlines and a milestone for some subitems - however we really want to be able to see the timeline bubble with range of dates/duration/fill as the timeline passes. It’s very useful for quickly identifying which tasks need to be worked 1st - the problem is when you set a milestone the range goes away and its just a date - so we added a 2nd timeline column to set the milestone separately - but now I need a way to autofill the milestone date based on the end date in the 1st timeline/range(or vice versa)

Every app I try either has additional cost or doesn’t support subitems - the company is not willing to pay additional funds for this - I was hoping there is a formula or automation that can achieve this for us.


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Hey Sara,

Firstly, thanks for this feedback. I hear where you’re coming from here and can definitely raise this with our team internally.

That said, in order to workaround this, can I ask if you can instead use a formula column to display the timeline end date to reference that milestone date?

Let me know what you think!

Thanks Bianca - I may be able to pull the end date via the above formula and then pull the date out again via a formula converting app like autoboost or general caster but it just occurred to me - I can’t auto set a date column to be a milestone…I can only do that with deadlines.

Is there a way that will auto set a date to a milestone? If not, we’ll manually have to set it anyway and might as well just set the date while we are there.
Either way, really appreciate the response and formula screenshot!

Hey Sara, thanks for your reply :pray:

Just to clarify, are you looking to auto set the date in the date column based on the milestone set in the timeline column? Or set a milestone in the date column based on the timeline set? Either way, I think we would need to integrate an app to achieve this, but I do want to be sure of your end goal here!

I would like the timeline to trigger a date as a milestone in a separate column - unless there is a way to set a milestone and keep the timeline date range vs being a single date…The latter would be ideal but I don’t think is possible.


Hm, is there specific logic to setting the milestone date from the timeline? I ask this as it would be possible to set this up in the formula column - for example to add days or subtract days from the timeline ends/start date!

Hi thanks. sorry I’m not being very clear and its confusing with two timelines doing two different things lol!

If I set a timeline as a milestone, I lose the date range and the bubble that fills as time passes - it allows for an easy way to find your next due task. Our team has requested that we do not remove the filling timeline. (pictured)

I could be wrong but I couldn’t find a way to set a milestone from a date column, only a timeline.

So essentially we need two timeline columns - one as a range of dates, one as a milestone/date only but we need the milestone date to be auto-filled from the end date of the range timeline. So once the range is filled out in the 1st timeline column, the end date would be pulled from that range and input into the 2nd timeline column as a milestone.

My last question was can you automate a date(timeline column) to set as milestone all the time (similar to set as deadline) I think it would be a manual task no matter what just because of the milestone setting being item specific instead of column specific.

If only the milestone didn’t remove the range…

I think I sort of answered my own question by thinking it out but if I’m wrong and there is a way please let me know!

Screenshot 2023-11-22 073810

No problem - apologies for my misunderstanding. Thank you for clarifying!

You’re correct - it isn’t currently possible to set a milestone in the date column (without simply inputting a date in the date column).

At this time, to set that milestone in the secondary timeline column, this will need to remain a manual process I am afraid, unless you set up a formula column to display that timeline end date, as we discussed earlier in the thread. Similarly, automating this process, to set a milestone each time a timeline is set isn’t currently supported. I have also tested with general caster (third party app) and haven’t been able to pull the end date from the timeline as we’d like :confused:

I hear where you’re coming from and completely agree that this would be an incredibly valuable feature - i.e. setting up a timeline + date column combo to account for that milestone date.

I will take this with our team internally and update you if there are any plans to develop this in the future :pray:

Thanks for your continued cooperation and patience Sara!

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I don’t know if it helps at all, but I just create Milestones as separate items, and then leave the work to be done for that milestone as items and subitems. You can create a dependency of those tasks that have the range of timeline for the milestone. Not sure if that solves the problem at all, but just wanted to give you a direction that I chose for managing this.