Compound Interest for $1 Million in a Savings Account If you go to the savings accounts page of MoneyRates.com, you can see the latest information on which banks are offering the best savings account rates . Synchrony Bank currently offers one of the highest yielding savings accounts in the country at 1.45 percent. That would translate into $14,579 of interest on one million dollars after one year of monthly compounding. The 10-year earnings would be $155,737. Compound interest works wonders over long periods of time. Here is an example of how much interest one million dollars would make in a year at a few different points based on a 4 percent interest rate compounded monthly. One Year – $40,741.54 Five Years – $220,996.59 Ten Years – $490,832.68 Twenty Years – $1,222,582.09.