The CDC has just updated its vaccine recommendations for “older adults” and immunocompromised adults to get a second dose of the updated vaccine. Since I’ve always been a stickler for documenting life events, I have my COVID-19 vaccine history listed in a Google Sheet. Now I wanted to now add a column that displays the interval between doses in months and days. Although I could have eventually determined the exact formula syntax (lots of trial and error), I opted to delegate this task to my trusty assistant: ChatGPT. Here’s how the conversation went with the chatbot:

Prompt: Create an Excel formula to convert a cell containing the number of days into a format of the number of months and days

Chatbot: Assuming you want to convert the number of days in cell A1 to the number of months and days in the format “Mm Dd”, you can use the following formula in Excel:

=TEXT(A1/30,"0")&"m "&TEXT(A1-INT(A1/30)*30,"0")&"d"

My ChatGPT formula was pretty close, but it incorrectly rounded the number of months. So I politely told it so:

Prompt: You’re getting closer, but that’s incorrect. The month calculation incorrectly rounds up by 1. 

Chatbot: You are correct, I apologize for the mistake in my previous response. Here is an updated formula that should work correctly:

=TEXT(INT(A1/30)&"m "&MOD(A1,30)&"d","0m ")&TEXT(MOD(A1,30),"0d")

Prompt: The month is right now, but the day is messed up.

Chatbot: I apologize for the mistake again. Here’s an updated formula to convert the number of days in cell A1 to the number of months and days in the format “Mm Dd”:

=CONCATENATE(IF(INT(A1/30)=0,"",INT(A1/30)&"m "),IF(MOD(A1,30)=0,"",MOD(A1,30)&"d"))

Now it’s right!

I invest $20 monthly in ChatGPT Plus, and for my needs, it’s a valuable tool and easily worth the investment since I use it daily across a wide array of tasks. While it may not be perfect (on the first try), neither are human assistants; however, both can provide significant support in managing my everyday knowledge-based work.