Savings Account Interest Calculator: How Much You’ll Actually Earn
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The single most important number when you compare savings accounts is APY (annual percentage yield) — but most savers can’t translate “4.50% APY” into actual dollars on their balance. This guide does that translation. We walk through the formulas, show real-world tables for $1,000 to $100,000 balances at 2026 APYs, and explain how monthly contributions and tax treatment change the picture. By the end you’ll be able to estimate your year-end interest in your head.
We pulled current rates from the top accounts in our broader 2026 reviews — UFB Direct (5.25%), Marcus (4.50%), Ally (4.45%), Discover (4.40%) — and used them in every example below.
How We Calculated These Numbers
The math is simple but the inputs matter. Most US online banks compound interest daily and credit it monthly. Our tables use the standard compound-interest formula:
A = P × (1 + r/n)^(n×t)
Where P is principal, r is the APY expressed as a decimal, n is the compounding frequency (365 for daily), and t is years. For monthly contribution scenarios we use the future-value-of-annuity formula on top of the lump-sum principal. All figures are pre-tax.
| APY | Compounding | Frequency | Effective annual yield |
|---|---|---|---|
| 5.25% APR (daily) | Daily | 365 | 5.39% APY |
| 4.50% APR (daily) | Daily | 365 | 4.60% APY |
| 4.50% APR (monthly) | Monthly | 12 | 4.59% APY |
| 4.50% APR (annually) | Annually | 1 | 4.50% APY |
| 0.42% APR (daily) | Daily | 365 | 0.42% APY |
Most banks quote APY directly, which already bakes in compounding. APR is rarer in savings products but appears on disclosures.
APY vs APR: What’s the Difference?
APR is the simple annual rate. APY includes compounding. Daily-compounded 4.50% APR turns into 4.60% APY because each day’s interest earns interest the next day. When you compare savings accounts, always compare APY to APY — that’s the apples-to-apples number that includes compounding.
Banks are required by Truth in Savings Act to disclose APY in advertising, which is why you’ll almost always see APY on rate sheets. CDs may be quoted in either APR or APY depending on the issuer.
Year-1 Interest at Top 2026 Rates
| Balance | UFB 5.25% | SoFi 4.60% | Marcus 4.50% | Ally 4.45% | Discover 4.40% |
|---|---|---|---|---|---|
| $1,000 | $53 | $46 | $45 | $45 | $44 |
| $5,000 | $263 | $230 | $225 | $223 | $220 |
| $10,000 | $525 | $460 | $450 | $445 | $440 |
| $25,000 | $1,313 | $1,150 | $1,125 | $1,113 | $1,100 |
| $50,000 | $2,625 | $2,300 | $2,250 | $2,225 | $2,200 |
| $100,000 | $5,250 | $4,600 | $4,500 | $4,450 | $4,400 |
These figures assume the rate holds for the full year. HYSAs are variable, so the actual interest credited will float with rate changes.
How Compounding Adds Up Over Time
A balance left untouched compounds. Over five years at 4.50% APY, $25,000 grows to $31,154 — a 24.6% gain without a single additional deposit. Run the same math at 0.42% (the national average) and you get $25,530 — a 2.1% gain. Same dollars, very different outcome.
| Years | $25K @ 5.25% | $25K @ 4.50% | $25K @ 0.42% |
|---|---|---|---|
| 1 | $26,313 | $26,125 | $25,105 |
| 3 | $29,135 | $28,517 | $25,317 |
| 5 | $32,288 | $31,154 | $25,530 |
| 10 | $41,705 | $38,824 | $26,065 |
Monthly Contributions Compound Faster
If you add $500/month to a $5,000 balance at 4.50% APY:
| Years | Total deposited | Final balance | Interest earned |
|---|---|---|---|
| 1 | $11,000 | $11,287 | $287 |
| 3 | $23,000 | $25,170 | $2,170 |
| 5 | $35,000 | $40,170 | $5,170 |
| 10 | $65,000 | $84,127 | $19,127 |
A $500/month habit at 4.50% turns $65,000 of deposits into $84,127 over a decade. Drop the rate to 0.42% and it would only grow to $66,400 — almost 18 grand of forgone interest.
Don’t Forget Taxes
Savings interest is taxed as ordinary income at federal and state marginal rates. A $1,125 interest payment at a 24% federal rate becomes $855 after federal tax — and less if your state imposes income tax.
Banks issue Form 1099-INT for any account paying $10+ in annual interest. Track the form for tax season; the IRS gets a copy too.
How to Use This Calculator in Practice
- Find your current account’s APY in the disclosure (not the marketing page).
- Multiply your average balance × APY to estimate annual interest.
- Compare with the top 2026 HYSA APY (around 5.25%).
- The difference is your “switching value” — what you’d earn by moving banks.
- Recheck quarterly — APYs change with the Fed.
Recommended Offers
💡 Editor’s pick: UFB Direct Secure Savings — 5.25% APY, the easiest single decision to add hundreds (or thousands) of dollars to your annual yield.
💡 Editor’s pick: Marcus by Goldman Sachs — 4.50% APY plus AutoSave to automate monthly contributions and capture compounding.
💡 Editor’s pick: Ally Online Savings — 4.45% APY with “buckets” so you can run separate calculations for separate goals inside one account.
FAQ — Savings Account Interest
Q: How is APY calculated? A: APY = (1 + r/n)^n − 1, where r is the annual rate and n is the compounding frequency. Daily compounding maximizes APY for a given APR.
Q: How often is interest paid? A: Most US online banks compound daily and credit interest monthly. CDs typically credit interest monthly, quarterly, or at maturity.
Q: Does interest compound on weekends? A: Yes — daily compounding means every calendar day, including weekends and holidays.
Q: Is HYSA interest taxable? A: Yes, fully taxable as ordinary income at federal and state marginal rates.
Q: How do I avoid taxes on savings interest? A: You can’t avoid it on a regular savings account. Use a Roth IRA for tax-free growth or municipal bond funds for federally tax-free interest.
Q: Can I lose money in a savings account? A: Not if you stay under the $250K FDIC limit. Inflation can erode purchasing power, but nominal principal is protected.
Related Reading on Finacial Qurio
- Best High-Yield Savings Accounts of 2026
- Best CD Rates of 2026
- Money Market vs Savings Account
- How to Build an Emergency Fund
- Roth IRA vs Savings Account
Final Verdict
Savings interest math is straightforward: balance × APY ≈ annual interest, compounded daily. The number people miss is the compounding tail — five and ten years of 4.50% APY meaningfully changes outcomes versus the national 0.42% average. If you take one thing from this guide, it’s that picking a top-rate HYSA is mathematically equivalent to giving yourself a small annual raise on every dollar you save. That’s a choice you can make this afternoon.
This article is for informational purposes only and is not financial advice. APYs, terms, and account features are accurate as of publication and subject to change. Finacial Qurio may receive compensation for some placements; rankings are independent.
By Finacial Qurio Editorial · Updated May 9, 2026
- savings
- interest calculator
- 2026
- high yield savings