"{triggercardcustomfieldvalue_Time}" is not a valid numeric value.
Asked by ale zan:

Hi!

I'm trying to write a Trello automation rule that when I add a card to the list "TODAY", it fetches the value of the custom field "Time" from this added card and adds it to the custom field "Time Total" of the card named "TIME TOTAL" already in the list TODAY.

I tried:
> when a card is added to list "TODAY",  
> find a card titled "TIME TOTAL" in list "TODAY",  
> and increase the number in custom field "Time Total" by {triggercardcustomfieldvalue_Time}

but it gives me the error:

"{triggercardcustomfieldvalue_Time}" is not a valid numeric value.

I also tried this:
> when a card is added to list "TODAY",  
> set custom field "Time" to "{{triggercardcustomfieldvalue_Time}}",  
> find a card titled "TIME TOTAL" in list "TODAY" on board "1W",  
> and set custom field "Time Total" to "{{cardcustomfieldvalue_Time Total}} + {triggercardcustomfieldvalue_Time}}"

but it gives me the error:  
The type of Custom Field "Time" (number) is not compatible with this action. This happens, for example, when you try to save text in a checkbox field, or to increase the content of a text field, or uncheck a number field, etc.  
"NaN" is not a valid numeric value.

Sure is some obvious noob mistake in using the variable, but if anybody would have a sec and patience to explain, would help a lot.

<br />

Thanks in advance


Answers:
author: Lara
body: Hi Ale,

Thanks for reaching out!

Could you please expand on your use case? Are you looking to have a card show the sum of all cards in the list with the TIME TOTAL Custom Field set?

If so, it might be better to use the [Dashcards Power-Up](https://trello.com/power-ups/6048e897c73d032a983e2a7c/dashcards). Here's how to track numeric Custom Fields using the Dashcards Power-Up: <https://support.atlassian.com/trello/docs/trello-dashcards/#Tracking-Numeric-Custom-Fields>.

Dashcards allow you to display the number of cards that match the filter as a card cover, and you can explore individual cards and metrics that make up the set.

Here's an example Dashcard configuration you could set up:

![Screenshot 2024-06-12 at 9.20.24?AM.png](https://community.atlassian.com/t5/image/serverpage/image-id/329605iD65912631339B26B/image-size/large?v=v2&px=999 "Screenshot 2024-06-12 at 9.20.24?AM.png")

Please let us know if you have any other questions, and we'll be happy to help.

All the best,

Lara  
The Trello Team


author: Hannah Humbert - Simpla Workflows
body: [@ale zan](/t5/user/viewprofilepage/user-id/3712266) can you give a bit more context into what you're trying to achieve? Are you wanting to use Trello for daily time tracking? Do you need historic reports of each day, or just a dynamic card that shows you the sum of the current day?  

You can use custom field arithmetic to calculate sums of custom field values, but you might run into issues with creating dynamic reports.   

Take a look at this post here where I gave some suggestions: <https://community.atlassian.com/t5/Trello-questions/How-to-assign-multiple-resources-and-estimated-time-per-resource/qaq-p/2031422>  

I recommended the use of Dashcards as it'll give you dynamic sums of cards, or the custom fields of cards. For example, you could filter it to only pull cards due today, or in a "Today" list, then have the report show the sum of a numerical custom field of all the cards that are included in that filter.