Savings calculator
APY Comparison Calculator
Compare two savings yield scenarios side by side. The calculator converts a stated annual rate and compounding frequency into an estimated annual percentage yield, then projects the balance over time.
Updated: June 10, 2026
Compare savings yields
Formula
Estimated APY is calculated as (1 + rate / compounds)compounds - 1. Ending balance is the starting deposit multiplied by (1 + APY)years.
Worked example
A $10,000 deposit earning a stated 4.25% compounded monthly will have a slightly higher effective annual yield than 4.25% because interest is added during the year.
How to interpret the difference
The difference result shows Scenario B ending balance minus Scenario A ending balance. A positive difference means Scenario B produced the larger estimate; a negative difference means Scenario A produced the larger estimate. Small APY differences may look minor over one year but become more visible over longer time horizons.
Use the same deposit and time horizon when comparing two rates. If one account has fees or minimum-balance rules, subtract those separately because this calculator focuses only on yield math.
Common mistakes
- Comparing promotional APY with a normal APY without checking expiration dates.
- Ignoring monthly account fees that can erase a yield advantage.
- Entering APY as a stated rate when the product already reports effective APY.
- Forgetting that taxes can reduce after-tax earnings.
Assumptions and limits
The calculation assumes the stated rate and compounding frequency remain unchanged for the full period and that interest stays in the account. It does not include new deposits, withdrawals, tiered rates, early withdrawal penalties, insurance limits, or account-opening restrictions.
Next steps
Verify whether each offer lists a stated rate or an APY, then compare disclosures for fees and minimum balances. For direct rate conversion, use the APR to APY calculator or the effective annual rate calculator. For a money market account estimate with monthly additions, use the money market calculator. For broader regular monthly additions, use the compound interest calculator; for a target amount, use the savings goal calculator.
FAQ
Is APY the only thing to compare?
No. Also compare fees, minimum balances, access limits, rate-change terms, and risk.
Why do compounding frequency and rate both matter?
A higher stated rate generally matters more, but more frequent compounding can slightly increase the effective annual yield.
Can taxes change the answer?
Yes. Taxes can reduce after-tax earnings and may change which offer is actually better for your situation.
How to read this yield gap
Read both ending balances and the difference together. This page is most useful when it shows whether stated-rate and compounding differences are large enough to matter after fees, minimum balances, promo windows, and tax drag are reviewed separately.
Before acting, compare result with account disclosures, APY or stated-rate labels, fee schedules, balance-tier rules, and promotional-rate expiration terms. See How We Calculate and the Disclaimer for more context.
Method and verification trail
- Method used: Each stated annual rate is converted into estimated APY from compounding frequency, then projected over selected years on same starting deposit.
- Primary source type to verify: Savings account disclosure, APY advertisement, fee schedule, balance-tier table, and promotional-rate terms.
- What to confirm in real documents: Whether quoted number is APY or nominal rate, whether compounding frequency matches disclosure, whether fees erase yield gap, and whether promo or tier rules require balance changes.
- Scope limit: This page does not fully model taxes, changing balances, new deposits, withdrawal limits, tiered-rate transitions over time, or provider-specific posting rules.
For site-wide methodology, review How We Calculate. For sourcing and corrections standards, review Editorial Policy.