So i got into a disagreement with ChatGPT about whether you earn more interest overall if you contribute daily rather than monthly, if the overall contribution over 1 year is the same.
I made CGPT write some python code to prove it. His code is on the left. I still didnt believe him so I wrote my own, on the right.
Our results seem to disagree, so Im asking you guys, if your interest is calculated daily and paid monthly, is it better to contribute $143 per day for 365 days, or $4349.58 monthly for 12 months?
No need to use a script, you can put the numbers directly into a financial calculator and use the TVM feature, or use the annuity formula directly (or annuity due if investing at the start of a period).
If you invest at the end of the period, daily is better, as more money will compound longer (vs waiting until the end of the month) If you invest at the beginning of the period, monthly is better (invest every at the beginning of the month)
Example with investing at end of period:
This is assuming you compound every day, as in practice, day count conventions may be different, and ignoring things such as the opportunity cost of the time spent time logging in to your bank to make daily transfers