Calculate start date + 3 months = DATE

I have a column [DELIVERY DATE] of a product, and the product has another column of [DURATION] example 3 months I want to calculate [DELIVERY DATE] + [DURATION] and the result I expect is in DateTime format in the [EXPIRATION] column
I really appreciate your help I’m new to appsheet

Please try

EOMONTH([Delivery Date], ([Duration] -1))+DAY([Delivery Date])

Here [Duration] is number type column that gives the number of months for expiry - such as 3, 5, 6 etc. Also [Delivery Date] is a date type column.

When expiration date is calculated to 29 or 30th Feb on non leap years and 30th Feb on leap years, The expression will automatically show a date of 1st March as there are no 29th and 30th Feb in non leap years and 30 th Feb in leap years.


Thanks for your answer, apparently if it works but there is a detail, example: I am calculating where the date in [Dedlivery date] is 11/04/2021 and [Duration] is a month 1 and the result that it gives me in column [ Date expiration] is 30/05/2021

is it possible to have 11/05/2021 as a result?

Please share the expression you are using and the type of each column in that expression.

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It calculates perfectly for me. Please recheck the column types and app formula with parenthesis etc. to ensure the formula works correctly. The below sample app test result is with exact identical column names and sample date as yours.

Please note the column types below. Please ensure [Duration] is number type column. By default AppSheet editor sets a column with name [Duration] as a type Duration.

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Dear @Suvrutt_Gurjar I am very grateful for answering my questions and for your valuable time.
My application is in Spanish, but the logic and the columns are the same here I leave the screenshots

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Hi @wsaico ,

Thank you for posting the screenshots. From the details shared , it sounds that you have made an error while entering the formula. You have entered [Expiration Date] in the formula , that is DAY([Expiration Date]) which is incorrect.

I have clearly mentioned that the formula has [Delivery Date] in all the places.

Please remove [FECHA VENCIMIENTO] from formula and include [FECHA ENTREGA] INSTEAD.

Please try


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oh! as I did not realize! Thank you very much for your help, it is already solved :blush: