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Savings calculator

See how an initial balance and regular monthly deposits could grow at a constant APY. Compare deposits at the beginning or end of each month, with contributions and interest shown separately.

Estimated ending balance(Example)

$12,954.52

View result

Your assumptions

Monthly deposit timing

Initial deposit: $0–$1 billion; monthly deposit: $0–$1 million; APY: 0–100%; 1–600 whole months. Rates accept up to 4 decimals.

Estimated ending balance

$12,954.52

Example only — edit inputs for your own estimate

Total deposits: $12,400.00
Estimated interest: $554.52

Constant APY converted to equivalent monthly growth, with one deposit each month. No withdrawals, taxes, fees, inflation, or rate changes. This is an estimate, not a bank quote.

Amounts display to cents. Calculations and CSV retain full precision, so rounded rows may differ by a cent. All amounts are USD.

Your inputs stay in this page. Calculator inputs are not sent to analytics or stored in the URL.

Read the calculation method

Monthly savings schedule

Monthly savings schedule
Month	Deposit	Estimated interest	Balance
1	$200.00	$40.74	$10,240.74
2	$200.00	$41.72	$10,482.46
3	$200.00	$42.71	$10,725.17
4	$200.00	$43.70	$10,968.87
5	$200.00	$44.69	$11,213.55
6	$200.00	$45.69	$11,459.24
7	$200.00	$46.69	$11,705.93
8	$200.00	$47.69	$11,953.62
9	$200.00	$48.70	$12,202.32
10	$200.00	$49.71	$12,452.03
11	$200.00	$50.73	$12,702.76
12	$200.00	$51.75	$12,954.52

How this savings calculator works

This is a hypothetical constant-rate projection in U.S. dollars. Enter an APY and positive monthly contributions; the example is not a bank offer.

Monthly growth and deposit timing

g = (1 + APY / 100)^(1/12); end: B_next = B × g + C; beginning: B_next = (B + C) × g

APY already includes annual compounding. We convert it to an equivalent monthly growth factor rather than compound the advertised APY again. Beginning-of-month contributions earn one additional month of interest relative to end-of-month contributions.

SEC Investor.gov: compound interest calculator

Contributions are not interest

Total deposits equal the initial balance plus monthly contribution multiplied by months. Earned interest is ending balance minus deposits. At 0% APY a $1,000 initial balance plus $100 for 12 months ends at $2,200, with no interest.

What this projection excludes

Rates are fixed for the full projection. Taxes, fees, inflation, withdrawals and daily deposit dates are excluded. Real savings-account rates can change. We retain precision in the calculation and round only for display; rounded schedule rows may not add exactly. Projection balances above $1 quadrillion are rejected.

Common questions

Can I use this for compound interest?

Yes, for a deposit balance with constant APY and monthly positive contributions. For a single CD deposit and simplified tax estimates use the CD calculator; for nominal-rate conversion use the APY calculator.

Are the example rates current bank rates?

No. All example rates are hypothetical. Enter a rate you have checked with your provider; this tool does not fetch offers or promise a return.

Methodology