How to use the HYSA calculator
Enter the APY exactly as your bank advertises it — typically a number like 4.50% or 5.00%. The calculator treats this as an effective annual yield, which is what APY means by definition, and converts it internally to the equivalent monthly rate before running the simulation. You do not need to adjust for compounding frequency.
The starting balance is what you have in the account today. The monthly deposit is the fixed amount you plan to add at the end of each month — set it to zero if you are modeling a lump sum only. The growth chart shows how the balance builds each year, with the lighter band representing your deposited principal and the remainder representing interest earned.
APY vs the nominal rate — why it matters here
When banks advertise a savings rate, they quote APY (Annual Percentage Yield) rather than the underlying nominal rate. APY already captures how often interest is applied — daily at most online banks — and expresses the total annual growth as a single percentage. Two accounts with identical APYs deliver identical growth over a year regardless of whether one compounds daily and the other monthly.
This calculator accepts APY as the input because that is the number on the bank's website. Internally it converts the APY to a nominal monthly rate using the formula r = 12 × ((1 + APY)^(1/12) − 1) before running the month-by-month projection. The result is mathematically equivalent to using the daily rate that produces the same APY, and accurately reflects what your account will actually earn.
HYSA vs traditional savings: the real difference
The national average savings rate has sat near 0.46% APY for much of recent history. Top HYSAs at online banks have been paying 4–5% APY — ten times or more. On a $10,000 balance over five years, the difference is approximately $2,500 in additional interest. On a $50,000 emergency fund, it approaches $13,000.
HYSAs at FDIC-insured online banks are covered up to $250,000 per depositor, carry no investment risk, and typically have no minimum balance and no monthly fees. The only meaningful trade-off compared to a traditional bank is that transfers can take one to two business days. For an emergency fund or a goal that is 12 to 36 months out, a HYSA is nearly always the better choice over a traditional savings account.
If you have a specific savings target in mind rather than a balance you want to grow, the savings goal calculator works in reverse: enter your goal and it tells you the monthly contribution needed or the timeline to reach it.
Frequently asked questions
How much interest does a high-yield savings account earn?
It depends on your balance, the APY, and how long you leave it. At 4.50% APY, a $5,000 balance with $250 added each month earns about $2,979 in interest over 5 years, giving you an ending balance of roughly $22,979. At a traditional savings account rate of 0.46% APY, the same scenario earns only about $313. The calculator above shows you the exact difference for your own numbers.
What is a good APY for a high-yield savings account?
As of 2024–2025, top HYSAs at online banks are offering 4.50–5.25% APY. The national average for traditional savings accounts sits near 0.46% APY. Anything above 4% is competitive in the current rate environment. Rates change with the Federal Reserve's benchmark, so the best strategy is to compare offers from several online banks whenever you open or renew an account.
Is the interest rate on a HYSA APY or APR?
Banks are required to quote savings rates as APY — Annual Percentage Yield — which already reflects the effect of compounding. This calculator accepts the APY you see advertised and treats it as an effective annual yield, converting it internally to the equivalent nominal rate before running the month-by-month projection. You should enter the APY exactly as shown on the bank's website.
How often does a high-yield savings account compound interest?
Most HYSAs compound daily and credit interest monthly. Compounding daily at a given APY produces the same effective yield as the quoted APY, so entering the advertised APY gives you the correct result regardless of whether the bank compounds daily or monthly. The APY standardizes all of that compounding behavior into one comparable number.
Does a high-yield savings account beat inflation?
When HYSA rates are above the inflation rate, your real purchasing power grows. At 4.5% APY with 3% inflation, your real return is approximately 1.5%. When rates dip below inflation — which has happened historically — a HYSA preserves liquidity and FDIC insurance but loses real value slowly. For longer time horizons, most financial planners pair a HYSA for emergency funds and short-term goals with diversified investments for longer-term wealth building.