APY Calculator – Savings Growth, CD & APR to APY, Free

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APY Calculator

See exactly what your savings earn — project growth with monthly compounding and contributions, convert APR to APY across compounding frequencies, and estimate CD earnings with early-withdrawal penalties. Instant, private, no signup.

✓ Savings Projection · ✓ APR⇄APY Converter · ✓ CD Penalty Estimator · ✓ Monthly Interest View

🔧 JS ⏳ · Input — · Result — · Engine ⏳

Initial deposit ($)

APY (%)

Years

Monthly contribution ($)

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Total interest

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Total deposited

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Interest per month (avg)

📅 Year-by-Year

Year	Interest earned	Total interest	Balance

💡 Interest compounds monthly and contributions are added monthly — matching how high-yield savings accounts actually work.

Rate (%)

Compounding Daily Monthly Quarterly Semi-annually Annually

Direction APR → APY APY → APR

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APR = nominal annual rate without compounding · APY = effective yield including compounding. Same rate, different numbers — banks quote APY on savings and APR on loans.

CD deposit ($)

CD APY (%)

Term 6 months 12 months 24 months 36 months 60 months

Withdraw after (months)

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Interest at maturity

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Penalty (est.)

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Net if broken early

⚠️ Early-withdrawal penalties vary by bank — commonly 3–12 months of interest depending on term. This uses a simple "months of simple interest" estimate; your bank's disclosure is authoritative.

APY vs APR — The Difference That Matters

APY (Annual Percentage Yield) includes the effect of compounding; APR (Annual Percentage Rate) does not. The same 4.4% nominal rate becomes 4.49% APY with daily compounding, 4.49% with monthly, and stays 4.4% with annual-only compounding. Banks quote APY on savings (higher number looks better) and APR on loans (lower number looks better) — same trick, opposite directions.

APY = (1 + APR ÷ n)ⁿ − 1   ·   APR = n × ((1 + APY)^1/n − 1)

Where n is compounding periods per year. The converter tab above flips both directions at any frequency — useful when comparing a daily-compounding HYSA against a monthly one, or decoding loan marketing. Rule of thumb: always compare APY to APY, never APY to APR, or you're comparing different units.

Why Use This APY Savings Calculator?

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Monthly Everything

Monthly compounding and monthly contributions — matching real HYSA mechanics.

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Monthly Interest View

See your average interest per month — the "my money earns $180/mo" number.

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APR ⇄ APY Bridge

Convert any rate at any compounding frequency, both directions.

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CD Penalty Math

Maturity interest plus an early-withdrawal penalty estimate — decide before breaking the CD.

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100% Private

Balances and rates never leave your browser — nothing sent or stored.

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Instant & Offline

Pure browser math on every keystroke — unlimited scenarios, no account.

Popular Use Cases

• 🏦 Project a high-yield savings emergency fund's growth with monthly top-ups
• 📍 Compare a 12-month CD against the savings account you'd otherwise use
• 🔄 Decode whether an APR-quoted product really beats an APY-quoted one
• 💵 See the monthly interest your balance generates — real passive income tracking
• 🎓 Learn compounding by watching the year-by-year table accelerate
• 🧾 Estimate the cost of breaking a CD early for a better rate elsewhere

Pro Tips for APY Math

• APY already includes compounding: a 4.5% APY account IS 4.5% effective annually regardless of compounding frequency — enter it with the Annual option to skip double-counting.
• Monthly compounding ≈ APY + ~0.04–0.1%: a 4.4% APR compounded monthly yields about 4.49% APY. Tiny per year, real money over decades.
• Contribution timing: this calculator adds monthly contributions at month-end — conservative versus accounts that pay from deposit day.
• CD laddering beats one long CD: splitting across 6/12/24/36-month CDs means regular liquidity plus rising rates — model each rung's APY here.
• Intro APYs expire: bonus-rate teasers often drop to near-zero after 3–12 months. Model year two at the base rate, not the teaser.

Frequently Asked Questions

Enter your deposit, the APY, and a time period above. The calculator compounds monthly (with optional monthly contributions) and shows your ending balance, total interest, and the year-by-year growth table. It's your savings future in two seconds.

A tool that projects how a savings account or CD grows using its Annual Percentage Yield — the effective yearly rate including compounding. This one also converts APR to APY, estimates CD early-withdrawal penalties, and shows monthly interest figures.

APY = (1 + APR ÷ n)ⁿ − 1, where n is compounding periods per year. A 4.4% APR compounded daily becomes about 4.49% APY. The converter tab above does it instantly, in either direction.

A $10,000 balance at 4.5% APY earns about $459 in the first year (compounding monthly), or roughly $38 per month. Add $200 monthly contributions and year five ends near $24,000 with about $2,300 earned in interest. Enter your own numbers for exact figures.

Yes — but always APY to APY. An account advertising a higher APR with annual compounding can actually pay less than a slightly lower APY with daily compounding. APY normalizes everything to one effective number; compare on that and the winner is real.

Banks charge an early-withdrawal penalty, typically several months of interest scaled to the term (often 3 months for short CDs, up to 12 for long ones). The CD tab estimates that penalty so you can see whether breaking early for a better rate elsewhere actually nets more.

Real banks calculate daily interest on the actual days in each month and your exact balance each day. This calculator uses clean monthly compounding — extremely close for planning, with small cent-level differences from daily-accrual accounts.

No. All math is JavaScript in your browser — deposits, rates and projections never leave your device. No account, no storage, and a refresh clears everything.