HYSA Calculator
See how fast your savings grow in a high-yield account — with monthly contributions and real compounding.
Project your savings growth
| Year | Balance |
|---|---|
| 1 | $12,899.11 |
| 2 | $15,928.67 |
| 3 | $19,094.57 |
| 4 | $22,402.93 |
| 5 | $25,860.17 |
What Is a High-Yield Savings Account?
A high-yield savings account (HYSA) is exactly what it sounds like: a savings account that pays a much higher interest rate than the traditional account at your local bank branch. While regular savings accounts often pay 0.01–0.50% APY, HYSAs from online banks typically pay 4–5% APY — roughly 10 times more — with the same FDIC insurance up to $250,000 per depositor, per bank.
Online banks can afford those rates because they don't pay for branches, tellers, marble lobbies, or expensive downtown real estate — the savings go straight into your APY. Your money sits in the same kind of insured account; it just earns while it waits. HYSAs are ideal for an emergency fund (3–6 months of expenses), a house down payment you're saving over 1–3 years, or any cash you need to keep safe and accessible.
What a HYSA is not: an investment account. It won't beat inflation by much, and it won't build retirement wealth like stocks. Its job is to protect short-term cash and pay you something decent for the privilege — and at 4.5% APY, "something decent" is very real money — earned with zero market risk.
How Compound Interest Grows Your Savings
Compound interest means you earn interest on your interest. Each month, the bank applies your APY to your balance — including last month's interest — so growth quietly accelerates. It's slow at first and powerful later, which is why starting early beats chasing a slightly higher rate.
The key term is APY (annual percentage yield), not the plain interest rate. APY already bakes compounding in: 4.5% APY means $10,000 genuinely becomes about $10,450 after one year, whether the bank compounds daily, monthly, or quarterly. When comparing accounts, compare APYs — the plain rate (APR) can mislead.
Monthly contributions supercharge the effect. Interest on a lump sum grows linearly-ish; interest on a lump sum plus $200/month grows on every deposit from the day it lands. That's why the calculator above has both inputs — most people's real savings story is "some now, some every month."
Worked Example: $10,000 at 4.5% APY
Lump sum only — 5 years
Step 1 — Monthly rate from APY: (1 + 0.045)^(1/12) − 1 = 0.3675% per month.
Step 2 — Growth factor: (1.003675)^60 = 1.246182.
Step 3 — Final balance: $10,000 × 1.246182 = $12,461.82.
Interest earned: $12,461.82 − $10,000 = $2,461.82 — free money for doing nothing.
Add $200/month
The deposits grow too: $200/month for 60 months at the same monthly rate adds $13,398.35 on top of $12,000 contributed. Total balance: $25,860.17. You put in $22,000; interest contributed $3,860.17.
Compare with a regular 0.40% account
Same $10,000 + $200/month at 0.40% APY grows to only about $22,320. The HYSA earns you an extra $3,540 — for the exact same deposits. That's the cost of leaving cash in a low-rate account.
HYSA vs Regular Savings Account
| HYSA (online bank) | Regular savings (big bank) | |
|---|---|---|
| Typical APY | 4.00–5.00% | 0.01–0.50% |
| $10,000 after 1 year | ~$10,450 | ~$10,010 |
| FDIC insured | Yes, up to $250,000 | Yes, up to $250,000 |
| Monthly fees | Usually $0 | Often $5–$12 (waivable) |
| Minimum balance | Usually $0 | Often $300–$1,500 |
| Access | App/ACH transfers (1–3 days) | Instant at branches/ATMs |
The trade-off is speed of access: moving HYSA money to your checking account takes 1–3 business days. For an emergency fund that's fine — true emergencies are rare, and the extra interest is constant. Keep one month of expenses in checking for instant needs; park the rest in the HYSA.
How to Choose the Best HYSA
- Compare APY, not brand. A 0.5% APY difference on $20,000 is $100/year. Check current rates — they move with the Fed — and don't assume the biggest bank pays the most (it usually pays the least).
- Confirm FDIC insurance. Look for "Member FDIC" and verify the bank at fdic.gov. Fintech apps that "partner with banks" are fine only if your specific deposits are insured — read the fine print.
- Watch for teaser rates. Some accounts advertise a high APY that drops after 3 months or requires a huge balance. Check the rate tiers and any balance requirements.
- Count the fees. The best HYSAs have no monthly fee and no minimum balance. Excess-withdrawal fees still exist at some banks (the old 6-per-month federal rule is gone, but bank policies linger).
- Test the transfers. Link your checking account and time a transfer before you need the money. Knowing it takes 2 days beats discovering it during an emergency.
Rates change, but the strategy doesn't: automate a monthly transfer the day after payday, and let compounding do the quiet work. Use the calculator above to set the target — then set the autopilot.
One last tip for rate chasers: moving banks for an extra 0.25% APY on a $10,000 balance earns you $25 a year. Automating an extra $50/month earns you $600 a year plus interest. Contribution size beats rate shopping almost every time — focus your energy where the dollars are.
My saved numbers reuse them in any calculator
Save a number once — like your rent or hourly rate — then just type its name instead of the number, in any calculator here. You can also type formulas like 5000 * 1.1 right into any box.
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Frequently Asked Questions
What is a good HYSA interest rate?
A good HYSA rate is typically 4% to 5% APY — roughly 10 times the national average for regular savings accounts. Rates move with the Federal Reserve, so compare current APYs from several online banks rather than relying on a fixed number.
How is HYSA interest calculated?
Banks apply your APY to your balance each compounding period (usually daily), including previously earned interest — that is compound interest. APY already accounts for compounding, so $10,000 at 4.5% APY becomes about $10,450 after one year regardless of compounding frequency.
Are high-yield savings accounts FDIC insured?
Yes — as long as the account is at an FDIC-member bank, deposits are insured up to $250,000 per depositor, per bank, exactly like a regular savings account. Always confirm "Member FDIC" before opening an account.
HYSA vs CD: which is better?
A HYSA keeps your money liquid — withdraw anytime with no penalty — while a CD (certificate of deposit) locks your rate for a fixed term but charges an early-withdrawal penalty. Choose a HYSA for emergency funds and short-term goals; consider a CD when you want to lock in a rate and will not need the cash.
How often is HYSA interest paid?
Most HYSAs compound daily and credit interest monthly. Because APY already includes the compounding effect, the payout frequency does not change your total — a 4.5% APY earns the same whether compounded daily or monthly.