# Increase according to month and automatic calculation

Hello guys!
I’m new here and I’m still learning about Airtable, but I’m really enjoying it!

I have some doubts about formulas, I would be very happy if they work for what I need, here are my doubts:

1 - Is there any way to add numbers in a column automatically every time you turn the month? For example: Column “parcels” on 12/22/2021 = 1 on 01/22/2022 = 2 and so on?

This would be very useful because here in Brazil we make purchases in installments, so the number of installments, changing month by month alone, would make it much easier.

2 - Is there any way for the formulas to understand the “unique selection fields”?

I would like to create a formula like: If the “unique selection field” has the option “green” the answer is 1, if it has the option “purple” the answer is also 1, but if it has the option "black " the answer is “1/2”

Assuming you have a {Start Date} field, where for the given example the start date was 12/22/2021, then a formula could be:

``````DATETIME_DIFF(
{Start Date},
TODAY(),
"months"
)
``````
``````SWITCH(
{Unique Selection Field},
"green", 1,
"purple", 1,
"black", 0.5
)
``````
1 Like

Great!! The formulas worked perfectly for what I needed, I’m enjoying the airtable even more now!

Thank you very much for your attention and help!

If not asking too much, could you help me with one more question?

I would like to know how I can multiply a result according to the responses of a “Unique Selection Field”. For example: Total Value = Unit Value * {Unique Selection Field}

I believe that for that I would have to create a column of reference and hide it there later, right? So I could follow the same logic you showed me.

Multiplication would be fairly straightforward

``````{Unit Value} *
SWITCH(
{Unique Selection Field},
"green", 1,
"purple", 1,
"black", 0.5
)
``````
1 Like

Perfect!! It worked great too!
Again, thank you so much for your patience and time, it helped me a lot.

Until later!

1 Like

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