Savings APY versus account fees: find the balance that changes the answer

The one formula you need

Break-even balance = extra annual fees divided by the APY difference as a decimal. A 0.5 percentage-point gap is 0.005; a $6 monthly fee is $72 a year; $72 / 0.005 = $14,400. Keep less than that in the account and the fee-free option comes out ahead.

This works because, for a one-year term, Regulation DD defines APY as interest earned divided by principal: interest for a year is roughly balance times APY. The formula assumes a constant rate, a balance that stays put for the year and fees paid from somewhere else. Savings rates are often variable, so treat the APY as a dated input, not a promise. [1]

Break-even balances at a glance

Balances below the figure favor the no-fee account. Original arithmetic, not bank quotes.

Worked example

Invented Account A: 4.0% APY, $6 monthly fee. Invented Account B: 3.5% APY, no fee. At $10,000, A earns $400 and pays $72 in fees, netting $328; B nets $350. A's higher rate leaves it $22 behind.

At $20,000, A nets $800 minus $72, or $728; B nets $700. Now A is $28 ahead. The crossover is $14,400, matching the formula.

Check whether the fee really applies to you

The CFPB notes banks and credit unions must tell you up front what monthly fees are and how to avoid them, cannot charge more than disclosed, and must notify you in writing before changing them. Common waivers are keeping a minimum balance or having paychecks or benefits directly deposited. [2]

If you will reliably meet the waiver, treat the fee as zero and the higher APY simply wins. If you might dip below the minimum balance even once a quarter, count those months' fees. The CFPB also suggests asking about lower-cost options, such as basic, student or senior accounts, or moving to an institution with low or no maintenance fees. [2]

Where the shortcut breaks

• Equal APYs: the account with the fee never catches up.
• Fee account has the lower APY: it loses at every balance.
• Fee deducted from the account itself: it also shrinks the balance earning interest; the gap is slightly bigger than the formula shows.
• Tiered rates or rate changes mid-year: calculate each period separately.
• Taxes: the IRS treats interest as taxable income in the year it becomes available, and you should receive a Form 1099-INT if you earn $10 or more. Taxes reduce both accounts' interest in proportion but do not refund fees. [3]
• Deposit insurance and access: confirm the exact institution and product and how quickly you can transfer money out; a brand name or app is not enough.