2026-09-21 7 min read

Savings Account Interest Calculator

Interest earned on a savings balance at APY.

Calculator

Initial Deposit Help

Lump sum you start with today.

Monthly Contribution

Annual Percentage Yield (APY)(%)

Time Horizon(years)

years

Extra Months(months)

months

This accounts & deposits calculator compounds monthly (12) at the nominal rate you enter, with contributions added at the end of each period. Compare accounts on APY — it already includes compounding.

Year-by-year growth

Balance, contributions and interest credited each year.

Year	Balance	Contributed	Interest
1	$12,866	$12,400	$466
2	$15,852	$14,800	$1,052
3	$18,964	$17,200	$1,764
4	$22,206	$19,600	$2,606
5	$25,585	$22,000	$3,585
6	$29,105	$24,400	$4,705
7	$32,773	$26,800	$5,973
8	$36,596	$29,200	$7,396
9	$40,578	$31,600	$8,978
10	$44,729	$34,000	$10,729

Results

Optimal

Projected balance

$44,729

APY entered

4.20%

Total interest earned

$10,729

Growth per $1,000 / year

$42

Live results update as you type — currently showing projected balance of $44,729 over 10 years. Replace the defaults with your own figures for an exact plan.

Visualizations

Interest earned each year

466$Y1

586$Y2

712$Y3

842$Y4

979$Y5

1,120$Y6

1,268$Y7

1,422$Y8

1,583$Y9

1,750$Y10

What makes up the final balance

Initial deposit22%

Contributions54%

Interest earned24%

Balance growth over time

Formula

APY already embeds compounding, so year-by-year growth is a single multiplication. Monthly contributions are converted through the equivalent monthly nominal rate for exactness.

Next-year balance ≈ balance × (1 + APY) + contributions

Variables

Symbol	Name	Unit	Description
APY	Annual percentage yield	%	Realised yearly yield after compounding
P	Balance today	$	Starting point
C	Monthly deposit	$	Added each month

Explanation

The balance shows deposits plus APY-driven interest — the number you will actually see on the statement if the APY holds.

Step-by-Step Calculation

Follow each step to understand how the result is calculated from your inputs.

Step 1

APY of 4.2% already includes compounding — use it directly for year-by-year growth

Balance × (1 + APY)

Result: $10,000 → $10,420 after year 1 (before contributions)

Step 2

Add $200/month through the year

Result: Year-1 balance ≈ $12,866

Step 3

Repeat for 10 years

Result: Final balance = $44,729 ($10,729 interest)

Final Answer

$44,729

Worked Examples

See how the calculator works with different scenarios.

Scenario

The savings account interest calculator run on the values above, showing the full calculation path rather than only the answer.

Inputs

Principal:10000

Monthly Contribution:200

Apy:4.2

Years:10

Calculation

1. APY of 4.2% already includes compounding — use it directly for year-by-year growth → $10,000 → $10,420 after year 1 (before contributions) 2. Add $200/month through the year → Year-1 balance ≈ $12,866 3. Repeat for 10 years → Final balance = $44,729 ($10,729 interest)

Result

Projected balance: $44,729

Interpretation

APY is the only rate you need for account shopping — it already reflects compounding frequency, so a 4.5% APY paid monthly beats a 4.5% nominal rate paid annually.

Understanding Your Result

Your Result: Projected balance: $44,729

Typical range: At 4.20% APY, every $10,000 earns about $420 in a year with no new deposits. Today's top high-yield accounts cluster near 4–5% APY.

What This Means

The balance shows deposits plus APY-driven interest — the number you will actually see on the statement if the APY holds.

Why It Matters

APY is the only rate you need for account shopping — it already reflects compounding frequency, so a 4.5% APY paid monthly beats a 4.5% nominal rate paid annually.

Professional Interpretation

APY is the only rate you need for account shopping — it already reflects compounding frequency, so a 4.5% APY paid monthly beats a 4.5% nominal rate paid annually.

How this is calculated

APY already embeds compounding, so year-by-year growth is a single multiplication. Monthly contributions are converted through the equivalent monthly nominal rate for exactness.

What drives the result

Balance growth at APY: next-year balance ≈ balance × (1 + APY) plus contributions. Nominal-to-APY conversion is EAR = (1+r/n)^n − 1; account shopping should always happen in APY space.

Recommendations

•Compare APY to APY, then check minimums, withdrawal limits and fees — the highest APY with a fee can lose.
•APYs float with central-bank rates: ladder CDs if you want to lock today's yield.
•At 4.20%,automating $200/month adds $24,000 of deposits over 10 years — usually more than the interest itself.

Educational Content

Introduction

APY is the realised yearly yield after compounding. High-yield savings, money-market and checking accounts differ in access rules and rate tiers, but the APY lets you compare them apples to apples.

Concept Explanation

Balance growth at APY: next-year balance ≈ balance × (1 + APY) plus contributions. Nominal-to-APY conversion is EAR = (1+r/n)^n − 1; account shopping should always happen in APY space.

Applications

▸Choosing a savings account

▸Pricing money-market vs checking balances

▸Projecting emergency-fund growth

Benefits

•One number compares any account
•Includes compounding automatically
•Makes teaser-rate math transparent

Limitations

•APYs are usually variable and can fall
•Tiers, caps, fees and balance requirements change the realised yield

Best Practices

•Compare APY first, then fees and access rules
•Keep emergency cash instant-access even at a slightly lower APY

Common Misconceptions

Myth: Checking accounts can’t earn interest

Truth: Many do — usually at a lower APY with balance caps.

Myth: Money-market accounts are market investments

Truth: In banking, “money market account” means an insured deposit account, not a fund.

Practical Tips

•Rank accounts by APY, then break ties on fees, minimums and access.
•Keep emergency cash instant-access even at a slightly lower APY.

Common Mistakes

Chasing APY into restricted accounts for emergency money

A 0.3-point premium is not worth losing instant access to the safety fund.

Assumptions

This calculator makes the following assumptions to provide estimates:

APY held constant: Variable APYs reset the trajectory whenever the bank moves.

Limitations

Be aware of these limitations when using this calculator:

Limitation: APYs are usually variable and can fall

Limitation: Tiers, caps, fees and balance requirements change the realised yield

Frequently Asked Questions

Answers to common questions about this calculator.

Is APY fixed?

Usually not — most savings APYs float with policy rates. CDs lock it for the term.

Who uses the savings account interest calculator?

It is used by savers planning deposits, by advisers comparing account yields, and by households pacing a savings account to a deadline. It sits in the Accounts & Deposits group of the Compound Interest & Savings section of Atlascalcs.

How accurate is the savings account interest calculator?

Every figure follows directly from the inputs using standard compounding mathematics, so it is accurate to the quality of the values you enter. Banks round interest and apply their own day-count and crediting rules, so expect small differences against a formal statement or maturity advice.

Do these calculators include taxes and inflation?

No — figures are before tax and in nominal terms. For a real-terms view, subtract your marginal tax drag and expected inflation from the rate before entering it.

Why does compounding frequency barely change my result?

Because at typical savings rates the periodic rate is tiny; frequency moves APY by hundredths of a point. Rate and time dominate — automate contributions and protect the horizon.

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Related Guides

Deepen your understanding with these educational resources.

Compound interest and APY guide

Nominal vs effective rates, compounding frequency and how to compare accounts.

Savings goals that actually get funded

Turning targets into automated monthly numbers with sinking funds.

CDs and ladders explained

When to lock a rate, when to ladder, and what early withdrawal really costs.

Glossary

Technical terms used in mortgage calculations explained in plain language.

APY (annual percentage yield): The realised yearly yield after compounding — the honest way to compare deposit accounts.
Nominal rate: The quoted annual rate before compounding is applied; divide by n for the periodic rate.
Compounding: Earning interest on previously earned interest; frequency is how many times a year it happens.

Authoritative References

Trusted sources and standards referenced by this calculator.

FDIC — Deposit insurance and savings account basics Consumer Financial Protection Bureau — Savings accounts Federal Reserve — Consumer credit and savings data (G.19) IRS — Interest income (Topic 403) U.S. Treasury — TreasuryDirect savings bonds

Applicable Standards

Discrete end-of-period compounding; contributions credited after that period’s interestAPY computed as (1 + nominal/n)^n − 1 on the quoted nominal rateMoney rounded for display only; all calculations run at full precisionDeposit figures before tax and inflation unless you enter a net rate

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Page Information

Last Updated:

2026-09-21

Version:

2.0.0

References:

License:

Free to use for educational and professional purposes.