About the Savings Account Comparison Calculator
This savings account comparison calculator puts up to three accounts head to head using your own balance and saving habits. Headline APYs rarely tell the whole story: a promotional 5% rate might apply only to the first $10,000, a big-bank account may charge a monthly maintenance fee, and another bank may dangle a cash bonus. Enter each account’s APY, any balance cap on that rate, the rate above the cap, the monthly fee and any one-time bonus, and the calculator shows how much each would leave you with after the number of years you choose.
Use it when switching banks, choosing between an online high-yield savings account and your current bank, or deciding whether a tiered “up to X%” offer beats a simpler flat rate. The winner often changes with the balance: tiered accounts favour small balances, while flat-rate accounts win as your savings grow — try a few amounts to see where the crossover sits.
Assumptions: interest compounds monthly at the APY’s equivalent monthly rate, the monthly fee is charged after interest, your deposit is added at the end of each month, and the bonus is paid as cash and not reinvested. Rates are held constant, although savings APYs are variable in practice. Tax on interest is ignored because it affects every account in proportion.
How to use the savings account comparison calculator
- 1Enter your starting balance, monthly deposit and how many years to compare.
- 2For each account, enter the APY and, if the rate is tiered, the balance cap and the rate above it.
- 3Add any monthly fee you would actually pay and any sign-up bonus.
- 4Check the best account and how far ahead it finishes.
- 5Try different balances to see where a tiered offer stops being the best deal.
Formula and method
Each account is simulated month by month. The APY is converted to its equivalent monthly rate so that twelve months of compounding reproduce the advertised APY exactly. When an account has a balance tier, the headline APY is paid on the balance up to the cap and the lower (or higher) rate on anything above it, as most tiered and “up to” offers work.
After interest is credited the monthly fee is deducted, then your monthly deposit is added. Any sign-up bonus is added to the final value as cash. The account with the highest ending value wins, and the net gain shows interest plus bonus minus fees over the period.
- B
- Account balance
- cap
- Balance up to which the headline APY applies (0 = no cap)
- i₁, i₂
- Monthly rates for the headline APY and the APY above the cap
- fee
- Monthly maintenance fee
Worked examples
$20,000 plus $500 a month for 3 years
Account A pays 4.3% on everything and ends at about $41,845. Account B’s 5% applies only to the first $10,000, with 1% above, so it finishes about $1,790 behind. Account C’s $200 bonus cannot make up for a 0.5% rate and $180 of fees.
Small balance: $5,000 plus $100 a month for 1 year
With a balance under the $10,000 cap all year, Account B’s promotional 5% beats Account A’s flat 4.3%, finishing about $39 ahead. Tiered accounts reward small balances.
$100,000 lump sum for 2 years with a $1,000 bonus
Account A’s 4% compounds to $108,160. Account C pays less (3.75%) but its $1,000 bonus lifts it to about $108,641, the best result. Account B’s 4.5% applies only to the first $25,000.
Frequently asked questions
How do I compare savings accounts?+
Compare the APY you will actually earn on your balance (check for tier caps and introductory periods), any monthly fees and how to avoid them, bonuses and their requirements, minimum balances, access to your money, and deposit insurance. This calculator rolls the money parts into one ending value.
What is a tiered savings account?+
A tiered account pays different rates on different balance bands, for example 5% on the first $10,000 and 1% above it, or a higher rate only once you pass a threshold. The advertised “up to” rate may apply to only part of your money.
Is APY or interest rate better for comparing accounts?+
Use APY (or AER in the UK). It includes the effect of compounding, so accounts that compound daily, monthly or annually can be compared directly. Two accounts with the same APY pay the same interest over a year regardless of compounding frequency.
Should I switch savings accounts for a bonus?+
A bonus is worth chasing when it outweighs the rate difference over the time you will hold the money. A $200 bonus beats a 0.5% higher rate on $10,000 for up to about four years, but not on $100,000. Check how long you must keep the money to earn it.
Do savings account rates change?+
Yes. Most savings and money market rates are variable and can change at any time, usually following central bank rate moves. Promotional rates often expire after a few months. Fixed-rate CDs or bonds lock a rate in exchange for tying up your money.
Results are estimates for educational purposes and are not financial advice. Rates, fees and terms vary — confirm with your lender or a licensed advisor before making decisions.