I'm trying to replicate the functionality of the Bankrate Simple Savings Calculator in Google Sheets. I've assumed that I need to use the FV function, but I can't get the numbers to match exactly. Here's what my Google Sheets spreadsheet looks like:
[A] [B]  Initial Deposit $100,000  Monthly Contributions $500  Over a period of 10 (years)  APY 2.4% FV $194,830.57 ...using =FV(B4/12,B3*12,-B2,-B1,0) Bankrate $194,410.60 ...using https://www.bankrate.com/calculators/savings/simple-savings-calculator.aspx FV - Bankrate = $419.97 difference ...why?
Using the FV function with a rate of 2.4/12, a number of periods of 10*12, a payment amount of -$500, and a present value of -$100,000 yields $194,830.57, but the same numbers in the Bankrate calculator come out to $194,410.60. This is a difference of $419.97.
I suspect that 2.4% APY in the Bankrate calculator is not the same as 2.4% in the FV function, but can someone explain why and how to fix the FV version so that it matches the Bankrate calculator? Thanks!