What Your Emergency Fund Actually Earns
Meet Dana. She has $25,000 sitting in a big-bank savings account paying 0.40% APY. That feels safe, so she never questioned it. Then she ran the math. At 0.40%, her emergency fund earns about $100 over a full year. The same $25,000 in a money market account paying 4.25% APY earns roughly $1,063. That's a $963 difference for moving money she wasn't touching anyway.
So what is a money market account? An MMA is a deposit account at a bank or credit union that usually pays more than a basic savings account in exchange for a higher minimum balance. It keeps the features Dana cares about: her money stays liquid, it's federally insured, and she can pull it out when an actual emergency hits. The trade-off is that the best rates often require keeping a minimum balance in the account.
Here's the part the rate sticker hides: tiered rates. Many MMAs don't pay one flat APY. They pay more as your balance climbs. A typical structure might look like this: balances under $10,000 earn 3.50%, $10,000 to $49,999 earn 4.25%, and $50,000 and up earn 4.50%. Dana's $25,000 lands in the middle tier at 4.25%. If she'd parked only $8,000, she'd have been stuck in the bottom tier earning 3.50% on the whole balance. The calculator applies the tier your balance qualifies for so you see the real number, not the headline rate the bank advertises for its largest depositors.
Then there's compounding. Most MMAs compound interest daily and pay it monthly. On a $25,000 balance at 4.25% compounded daily, Dana earns a few dollars more per year than simple interest would give her, and that gap widens as the balance grows. Enter your deposit, the APY your bank quotes, and how long you plan to leave the money, and the calculator shows your projected balance and total interest earned. Suddenly the choice between accounts isn't a guess about which one sounds better. It's a number you can see.