How to sum tasks with weight, to decide a percentage of all project?

Hi @Cristiano_Vani,
Here is a Switch formula you can use to show you the percentage based on the Status of the task;

SWITCH(
  Status,
  'To Do', .05,
  'Doing', .40,
  'Validation', .05,
  'Done', .50
)

Format the formula field to Percentages

I do not understand how you will add up to 100% as the status changes. Do you intent to store the percentage as you move through the process?

Maybe this formula makes more sense?

SWITCH(
  Status,
  'To Do', .05,
  'Doing', .45,
  'Validation', .50,
  'Done', 1
)

It helped me a lot, thanks u guys!
But, now I have another question, a little bit harder I think

Each task have a weight (5%, 40%…)
Each task have a representative weight, but, all the tasks is equal in importancy
So, if I have 15 tasks inside a project, each task represents 6,67%, ok?
If I have 5 tasks inside a project, each tasks represents 20%, ok?

So, I have 15 projects and 105 tasks in total, like this:

Tasks %Project
6 5,71%
15 14,29%
7 6,67%
6 5,71%
5 4,76%
6 5,71%
8 7,62%
6 5,71%
5 4,76%
16 15,24%
9 8,57%
4 3,81%
6 5,71%
6 5,71%
0 0,00%
105 100%

Because 6/105 = 5,71%, like this.

Now, I need to know, the progress of my project with the percentage of the tasks.

Tasks
5 Weight Project Weight
to do 5% 0,05%
doing 40% 0,38%
done 50% 0,48%
doing 40% 0,38%
backlog0% 0,00%
1,29%

When all the tasks are done, the total is 4,76% in this case.
So, how I can put this, inside the Airtable?

If it doesn’t clear, pls tell me, I’m trying to explain all the points

If I have understood

Have a look at creating a roll up field in the projects field with the number of tasks - then lookup this field in all of the tasks then use it in a formula to divide the progress of each task by to create proportion of project complete by this task.

You can then roll these fields up into the project field for completion.