A bank bonus versus HYSA calculator answers one question: does moving money to earn a sign-up bonus pay more than leaving it in a high-yield savings account? The inputs are the bonus amount, the deposit the bank requires, how long the money must sit, your HYSA's APY, and your marginal tax rate — and the result is a simple after-tax dollar comparison over the offer's time window. The rate backdrop matters more than it used to. The Federal Reserve raised the federal funds target range to 3.75%–4.00% on September 16, 2026 — its first hike since 2023, per the Fed's announcement — so a calculator built around "falling rates" needs its APY-path assumption flipped: savings yields are now expected to hold or climb.
Table of Contents
- The inputs that actually drive the result
- How the comparison works
- The assumptions the calculator must state
- Taxes hit both sides — but not equally in practice
- Reading the results and deciding
- Frequently Asked Questions
The inputs that actually drive the result
Five numbers decide the outcome. The bonus amount and the required deposit set the headline ratio; the hold period and your HYSA rate set what you give up; your tax rate adjusts both sides. For the HYSA field, use a real current rate, not a stale one.
NerdWallet's September 2026 survey puts top accounts at roughly 3.75%–4.21% APY, with Axos One at up to 4.21% and Newtek at 4.20%. If your money currently sits at a big traditional bank, the right baseline is instead the FDIC national average savings rate of 0.38% — the forgone yield is tiny, and almost any bonus wins. Concrete example inputs: Chase pays a $400 bonus on Total Checking for $1,000 or more in direct deposits within 90 days, an offer running through October 14, 2026, according to NerdWallet's Chase bonus guide.
How the comparison works
The math is forgone yield versus bonus dollars. Money parked in a checking account paying about 0.07% (the FDIC average for interest checking) instead of a ~4% HYSA gives up roughly $10 per month for every $3,000 held. Run the Chase example: $1,000–$2,000 parked for 90 days forgoes perhaps $10–$20 of HYSA interest. The $400 bonus beats that by a factor of twenty or more.
That margin is typical when deposit requirements are modest. The ratio varies enormously by offer, though. Bankrate's September 2026 roundup shows KeyBank paying $300 for $2,000 in direct deposits, Huntington paying $400 for a single $500 direct deposit, and Huntington's Platinum Perks paying $600 for $25,000 in new money. That last one ties up serious capital: $25,000 out of a 4.2% HYSA forgoes about $260 over three months, cutting the effective gain to roughly $340 before tax.
The assumptions the calculator must state
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- Rate path: don't hard-code declining APYs. After the September hike, futures markets price the funds rate near 4.2% by December 2026 and about 4.6% by September 2027. A falling-rate assumption understates HYSA earnings and overstates the case for bonus chasing.
- Eligibility: many banks bar recent bonus recipients. Chase allows one new checking bonus per two years and excludes existing checking customers.
- Timing: bonuses can post up to 15 days after requirements are met, so the money may sit longer than the stated window.
- Fees: a monthly maintenance fee can eat the bonus if you miss the waiver conditions. Model the fee as a negative line item unless you're certain of the waiver.
Taxes hit both sides — but not equally in practice
Sign-up bonuses are taxable as ordinary interest income. Banks report them in Box 1 of Form 1099-INT when your total interest exceeds $10, and per The Points Guy's tax guide, the income is reportable even if no form arrives. Because HYSA interest is taxed the same way, applying your marginal rate to both sides shrinks the dollar gap but rarely changes the winner.
A $400 bonus at a 24% marginal rate nets $304; the $15 of forgone interest it beat nets about $11. The ranking survives taxation whenever the pre-tax ratio is lopsided. Where taxes do change decisions is at the margins: a $600 bonus requiring $25,000 in new money nets roughly $260 after 24% tax and forgone after-tax HYSA interest — still positive, but close enough that a posting delay or missed fee waiver could erase it.
Reading the results and deciding
Convert the output to an annualized rate on the money committed to make offers comparable. The Chase example — $400 net of a small yield loss, on $1,000, over roughly 90–105 days including posting time — annualizes to well over 100%. The Huntington Platinum Perks example annualizes closer to 4–5 percentage points above the HYSA, a real but modest edge.
Then weigh what the calculator can't price: the direct-deposit switch, the risk of missing a requirement, and the two-year cooldown you spend at that bank. A high annualized rate on a small deposit is usually worth the paperwork; a thin edge on $25,000 often isn't. One practical order of operations: keep your emergency fund in the HYSA, meet direct-deposit bonuses with amounts near the minimum, and only commit large "new money" balances when the after-tax edge over your current APY exceeds what a 15-day posting delay could erase.
Frequently Asked Questions
Should the calculator assume savings rates will fall?
No. After the Fed's September 16, 2026 hike, markets price rates near 4.2% by December and roughly 4.6% by September 2027, so flat-to-rising APY paths are the realistic default.
What HYSA rate should I enter?
The rate you actually earn. Top online accounts pay 3.75%–4.21% APY as of September 2026; the FDIC national average is just 0.38%, the right baseline if your cash sits at a big traditional bank.
Is the bonus taxed differently than interest?
No — both are ordinary interest income, typically reported on Form 1099-INT, and reportable even without a form.
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