Savings Account Comparison Calculator

Read the calculator result

A higher savings APY doesn’t always leave you with more money. A monthly service fee, an opening cost, or the cost of moving an account can offset additional interest. This calculator follows two accounts from the same starting cash through the same monthly deposits and comparison period.

Account A represents one set of terms. Account B represents another, with an optional one-time switching cost. The result shows each ending balance, gross interest, recurring fees, and the difference between the accounts. You supply the APYs and costs; the figures shown initially are illustrations, not current bank offers or a ranking of financial institutions.

Use the comparison to answer a specific question: would the second account leave more cash over the period you expect to use it? Access, minimum balances, variable-rate conditions, and service features still need separate review because the model doesn’t determine whether an account is appropriate or available to you.

Savings account comparison: enter APYs without compounding them twice

APY is an effective annual yield that already reflects compounding. Regulation DD’s APY methodology explains the relationship between interest and compounding in deposit-account disclosures. Enter a quoted APY in the APY field, rather than substituting a nominal interest rate that has a different meaning.

The calculator converts each APY to an equivalent monthly growth rate using monthly rate = (1 + APY ÷ 100)^1/12 − 1. This creates twelve equal mathematical months. It doesn’t reproduce a bank’s daily accrual calendar, interest-crediting dates, leap-year treatment, or statement rounding.

Dividing APY by twelve and then compounding that monthly figure would generally produce more than the entered annual yield. That’s why the conversion uses a twelfth root. If you have a nominal rate and a compounding frequency instead, the APR to APY calculator can illustrate the mathematical conversion, subject to its distinction between nominal rates and fee-inclusive loan APRs.

How the calculator works

Starting cash is the money available under either option before switching costs. Account A begins with that full amount. Account B begins with starting cash minus its one-time switching cost. This keeps the upfront cash commitment equal: paying a $50 cost means $50 less is initially available to earn interest in B.

Both accounts receive the same end-of-month contribution for the same number of months. The tool first applies interest to the opening balance, then adds the contribution and subtracts the monthly fee. A new deposit therefore starts earning modeled interest in the following month. Fees reduce future balances and future interest.

Enter the fee you expect to pay under the actual conditions. Regulation DD’s account-disclosure provisions address rate variability, balance requirements, and account fees separately. A fee waived only after qualifying activity can’t safely be entered as zero unless your scenario assumes that condition is met throughout the period.

The calculator rejects a switching cost greater than starting cash and any monthly path that produces a negative balance. Those are boundaries of this savings model. They don’t predict how a bank would handle an insufficient balance, assess a charge, close an account, or waive a fee.

Savings account comparison calculator example: a higher APY with recurring fees

Start with $10,000 and deposit $200 at the end of each month for 24 months. Account A has an illustrative 4% APY and no monthly fee. Account B has a 4.5% APY, a $5 monthly fee, and a $50 one-time switching cost. The same $14,800 of starting cash and new deposits is committed to either choice.

Account B earns more gross interest, yet finishes $52.26 below A. Its $170 of explicit costs outweigh the extra interest over this horizon. B’s net growth above the $14,800 committed is $948.86, compared with $1,001.12 for A. The comparison uses unrounded monthly calculations and rounds the displayed currency to cents.

Reconcile B’s result as $14,800 of committed cash plus its unrounded interest, minus $120 of monthly fees and $50 of switching cost. Don’t subtract the switching cost again from the displayed ending balance; it was already removed at the start.

Also distinguish growth from contributions. Dividing the ending balance by the original $10,000 would treat the additional $4,800 you deposited as an investment gain. That ratio isn’t this account’s APY or personal return. The interest and fee totals provide the relevant reconciliation because the tool knows when each monthly contribution enters the balance. A personal annualized return would require a separate cash-flow return calculation.

Test whether a fee waiver changes the result

Keep all the example inputs but set B’s monthly fee to zero. Its ending balance becomes $15,874.07, putting B ahead by $72.95. The $50 switching cost still applies. This shows why confirming fee-waiver conditions can matter more than comparing the advertised yields alone.

Removing $120 of fees increases B’s ending balance by about $125.21, rather than exactly $120. Money that would have paid earlier fees now stays in the account and earns additional interest. That effect is already in the month-by-month balance. Adding a separate estimate of “lost interest on fees” would double-count it.

If both the monthly fee and switching cost are zero, B ends at $15,928.67, or $127.55 above A. These are separate scenarios, not three benefits to add together. Change one assumption at a time and record the result so you can see which condition causes the difference.

Match the horizon to the decision

A one-time switching cost is especially visible over a short holding period. With the original fees and a twelve-month horizon, A ends at $12,843.69 and B at $12,785.63. B remains behind by $58.06. Extending the period changes both the extra interest and the cumulative monthly fees, so a longer horizon doesn’t automatically make switching worthwhile.

The size and timing of deposits also matter. When an account charges a fixed dollar fee, that fee has a larger impact relative to a small balance. The model doesn’t change fee rules as balances grow. If a bank has tiers or a minimum-balance waiver, divide the situation into clearly stated scenarios or use a model that follows those actual rules.

The balance chart follows both accounts over the selected months. Account B may start lower because of its upfront cost. A crossing of the lines would be a modeled balance crossover under constant assumptions, not a promise that future rates or account conditions will stay unchanged.

Use the comparison with the account terms

Gather each account’s APY, rate-change language, fee schedule, qualifying balances, and withdrawal or transfer conditions. Record when the information was checked. A result based on an introductory rate held constant for several years can substantially overstate interest after the promotion ends.

Check which fees are incremental to the decision. A charge you would pay regardless of account choice belongs outside this difference unless it’s entered consistently on both sides. Conversely, an actual closure, transfer, or required setup cost shouldn’t disappear merely because it’s paid from another account; the comparison assumes the same starting cash funds B’s switching cost.

Consider the purpose of the money. A small projected advantage may have limited value if a transfer delay prevents paying a bill on time. The sinking fund planner helps assign money to upcoming deadlines, while the CD ladder calculator examines balances released at different maturities. Those tools answer different timing questions from this account-balance comparison.

What the comparison leaves outside the result

The calculation excludes income taxes, bonuses, variable-rate resets, tiered yields, conditional fee changes, transfer delays, and differences in deposit availability. It doesn’t verify an institution, account insurance, or eligibility. Any of those conditions can matter even when the arithmetic difference is small.

Zero APY is a useful check. With both APYs set to zero in the original example, A ends with $14,800 and B with $14,630. The $170 difference is exactly the entered fees. With positive yields, the same charges also change the interest earned on later balances.

Savings account comparison calculator questions

Is the result the same as a bank statement?

No. It’s an equal-month projection using constant APYs. Actual statements can reflect daily balances, exact transaction dates, rate changes, and institution-specific rounding. Use the calculator for scenario comparison and reconcile real statements with the account terms.

Does the monthly-fee total for B include switching cost?

The recurring monthly-fee result excludes the one-time switching cost, which is shown separately. The cumulative fees in the detailed schedule include the switching cost so the balance reconciliation remains complete.

Can I compare accounts without making new deposits?

Yes. Set the monthly contribution to zero and compare the same starting cash over the desired period. Fees still apply under the entered assumptions, so ensure the balance remains sufficient throughout the scenario.

Does a positive B advantage mean I should switch?

It means B has the higher ending balance in this calculation. Review access, conditions, service, and the reliability of the assumptions before making an account decision. The calculator supplies a dollar comparison, not a product recommendation.