See what your cash actually earns.
Most people leave their savings in a regular checking or savings account earning almost nothing, losing real money to inflation every year. This tool shows the gap between letting cash sit and letting it work, across the three places people most commonly keep short-term money. Adjust your starting balance, what you'd add, how often, and over how long. Watch the piggy bank fill up.
How much you have right now
Each weekly
Every week
How long the money stays put
Adjust interest rates+
Defaults reflect typical 2026 rates. Adjust to match your actual account if you want. Enter the nominal annual rate. The projection compounds it monthly, so the effective yield (APY) comes out a touch higher than the rate you type.
That's $7,327 in interest on top of the $27,000 you actually put in. That's $7,257 more than the same money would earn in regular checking.
Where cash actually grows.
Most checking accounts pay almost no interest. Money sits, but it doesn't grow.
Traditional savings at a big bank. Better than checking, but still well below inflation.
Online savings accounts. FDIC-insured. Rate is variable, moves with Fed policy.
Money market accounts work a lot like high-yield savings.
FDIC-insured, similar APYs, sometimes with check-writing or debit access. Often have higher minimum balance requirements. They can be a fine alternative to an HYSA, but watch out for one common mix-up:
For money you won't touch for a while, there are longer-term options.
For cash you can lock up for 6 months to several years, these can sometimes earn a bit more, usually with rules about when you can access it. Each works differently. None of them are "better" or "worse", they just have different tradeoffs.
Education only. None of these are recommendations, just options worth understanding.
Convert your contributions to a smooth monthly stream. Over 10 years that adds up to $26,000 on top of your starting balance.
Monthly contribution = (contribution * contributions per year) / 12
A one-time deposit is added to the starting balance up front instead of streaming in.
Each account compounds the same balance month by month at its own annual rate (0.05% checking, 0.40% regular savings, 4.50% high-yield), for 10 years.
New balance = previous balance * (1 + annual rate / 12) + monthly contribution
The rate is compounded monthly, so the realized yield (APY) comes out a touch above the rate you enter.
The gap between the high-yield account and plain checking is the headline number.
Gap = $34,327 - $27,070 = $7,257
A few things this calculator simplifies.
Interest rates change. Savings APYs aren't fixed. When the Federal Reserve adjusts the federal funds rate, savings rates follow. The 4.5% HYSA rate that looks great today might be 3% in a year, or 6%. The defaults shown reflect typical rates as of early 2026.
Inflation isn't included. Earning 4.5% in an HYSA when inflation is running at 3% means you're really only gaining about 1.5% in purchasing power. That's still better than checking (where you're losing roughly 3% against inflation), but the headline numbers above don't show this.
Taxes matter. Interest earned in any of these accounts is generally taxed as ordinary income at the federal level, plus state tax in most states. So the after-tax interest is lower than the headline. (Tax-advantaged accounts like Roth IRAs are a different story, see those lessons.)
FDIC insurance has limits. FDIC insurance covers up to $250,000 per depositor, per FDIC-insured bank, per ownership category. People with larger balances often spread money across multiple banks for that reason.
Assumptions
- Rates are constant for the full horizon. Real account rates move with the Federal Reserve's federal funds rate, sometimes substantially within a year.
- The entered figure is a nominal annual rate compounded monthly, not an APY. Default rates reflect typical early-2026 levels: roughly 0.05% checking, 0.40% regular savings, 4.50% online high-yield savings. Real rates vary across institutions and over time.
- Contributions stream in evenly across each year regardless of the frequency selected.
- FDIC insurance is assumed on all three balances (covered up to $250,000 per depositor, per bank, per ownership category).
Limitations
- No taxes. Interest earned in any of these accounts is generally taxed as ordinary income at the federal level, plus state tax in most states. The displayed interest is pre-tax.
- No inflation. Earning 4.5% in an HYSA when inflation runs 3% means a real (after-inflation) return closer to 1.5%.
- No bonus tiers or balance caps. Some HYSAs cap the rate above a certain balance, or offer a promo rate that resets after a window.
- No early-withdrawal penalties, transfer delays, or balance-minimum fees.
- It is not a recommendation of any specific bank or product.
- It is not a prediction of where APYs will go. Rates move with Fed policy.
- It is not after-tax or after-inflation. Both reduce the real value of the headline number.
- It is not personalized advice on where to keep your emergency fund.
Educational simulation only. Real interest rates vary, change over time, and are reduced by inflation and taxes. FDIC insurance covers deposits up to $250,000 per depositor per insured bank. Past performance does not guarantee future results. This is not personalized financial advice.