Recurring Savings Calculator
Enter your monthly deposit, annual rate, and term on the left, along with simple or compound interest and whether the account is taxable, and see your estimated maturity value, pre- and after-tax interest, and how the balance builds up over time as a chart and a schedule on the right.
Inputs
Savings plan
Interest & tax
Enter your monthly deposit, rate, and term to see the result.
Result
Enter a deposit, rate, and term to see how deposits and interest build up over time.
- Total deposits
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- Pre-tax interest
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- Estimated tax (~22%)
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- After-tax interest
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- Effective yield
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- Term
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Schedule
| Enter your plan to see the month-by-month schedule. |
Things to check
This is an estimate based on standard recurring-deposit math. Simple interest credits each deposit for the months remaining to maturity; compound interest adds interest to the balance each month. Interest from a savings account or CD is taxed as ordinary income, not at a single flat rate — the "taxable" option uses a representative 22% marginal rate, but your actual rate depends on your federal tax bracket and your state. Tax-advantaged accounts (such as a Roth IRA or HSA) can grow tax-free if you meet the rules. Confirm the exact figures with your bank or credit union.
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How a Recurring Savings Balance Grows: Deposits, Interest, and Tax
The maturity value of a recurring savings plan comes down to your monthly deposits plus the interest each deposit earns for the time it sits in the account — minus the tax on that interest. Because the rate isn't applied to your full balance for a whole year, the headline APY alone doesn't tell you what you'll actually receive, so this tool lays it out with inputs on the left, results on the right, and a growth chart and schedule below.
The figures here are an estimate based on standard recurring-deposit math. Your actual result can vary with your bank's compounding method, rounding, and your personal tax situation.
What a recurring savings plan actually returns
A recurring savings plan — an automatic monthly transfer into a savings account, a "add-on" share certificate at a credit union, or a savings-goal account — builds a balance from level monthly deposits plus interest. Your deposits are simple to total, but the interest depends on how long each deposit has been earning, which is why the APY alone can be misleading.
- Total deposits = monthly deposit × number of months
- Maturity value = total deposits + after-tax interest
- After-tax interest = pre-tax interest − tax on the interest
Reading the inputs and result
On the left, enter your monthly deposit, annual rate (APY), and term, then choose simple or compound and taxable or tax-advantaged. As you change values, the maturity value, balance-growth chart, pre- and after-tax interest, and the month-by-month schedule update instantly. There is no calculate button.
Simple vs. compound interest
Simple interest credits each deposit only for the months remaining until maturity. Compound interest adds each month's interest to the balance so it earns interest too. With the same rate and term, compounding returns more — many everyday savings accounts compound daily or monthly, while some fixed products use simple interest, so check your terms.
- Simple: each deposit earns rate × months remaining
- Compound: each month (balance + deposit) × (1 + monthly rate)
- The longer the term and higher the rate, the bigger the gap
The simple-interest formula, worked out
The first deposit earns interest for n months, the second for n−1 months, and so on down to the last deposit's single month. Adding those up gives pre-tax interest of monthly deposit × monthly rate × n(n+1)÷2.
- Pre-tax interest = monthly deposit × (annual rate ÷ 12) × (n × (n+1) ÷ 2)
- Example: $500/month at 4% for 36 months → 500 × 0.003333 × 666 ≈ $1,110
- On $18,000 of deposits, that adds about $1,110 in pre-tax interest
How savings interest is taxed in the U.S.
Interest from a savings account or CD is taxable as ordinary income in the year it's credited, and your bank reports it on Form 1099-INT (issued if you earn $10 or more). There's no single flat withholding rate — the tax you owe depends on your federal bracket and your state's income tax.
- Interest is ordinary income, reported on Form 1099-INT
- This tool uses a representative 22% marginal rate for "taxable"
- Your real rate depends on your bracket and state — treat after-tax as approximate
Growing savings tax-free
Some accounts shelter growth from tax. In a Roth IRA, qualified withdrawals — including earnings — are tax-free; an HSA can be triple-tax-advantaged for medical costs. Choosing "tax-advantaged" here sets the tax to zero. These accounts have contribution limits and eligibility rules, so confirm what applies to you before relying on the tax-free result.
APY vs. effective yield on deposits you add over time
Because you add money gradually rather than depositing a lump sum up front, the APY isn't applied to your whole balance for the full term. As a result, the effective yield — the after-tax interest as a share of your total deposits — is lower than the headline APY, often roughly half over a multi-year recurring plan.
- Effective yield = after-tax interest ÷ total deposits × 100
- A recurring plan's effective yield runs below its stated APY
- A lump-sum deposit earns on the full amount from day one, so its yield is higher
Reading the growth chart and schedule
The chart shows deposits (lower area) and interest (upper band) building over time, with a solid line for the total balance and a dashed line for deposits alone. The table below lists cumulative deposits, cumulative interest, and the ending balance at each checkpoint. All amounts are pre-tax; tax applies to the interest at maturity.
Recurring savings vs. a lump-sum CD
A recurring plan spreads deposits over time; a standard CD locks in a lump sum at once. At the same APY, the lump sum earns on the full amount from day one, so it produces more interest. A recurring plan wins on habit and cash-flow flexibility — you save as you go — while a CD suits money you already have and won't need until maturity.
Watch the fine print on the rate
The rate in an ad is often the top APY that assumes conditions — direct deposit, a minimum balance, or a relationship discount. Miss them and you fall to a base rate, which lowers your maturity value. Enter the APY you will actually earn, and check whether the rate is fixed for the term or can change.
Common mistakes
Recurring savings looks simple, but a few assumptions trip people up.
- "I'll earn the full APY" — on a recurring plan the effective yield is lower
- "Tax comes out of my principal" — only the interest is taxed
- Forgetting that variable savings rates can drop mid-term
- Assuming a fixed product compounds when it actually uses simple interest
- Using the promotional top rate without meeting the conditions
A checklist before you rely on this estimate
Running through these first will bring the estimate closer to your real statement.
- Is the rate the APY you'll actually earn, not the promotional top rate?
- Does the account use simple or compound interest?
- Is it taxable, or a tax-advantaged account like a Roth IRA or HSA?
- Can you keep the monthly deposit going for the whole term?
- Is the rate fixed for the term, or can it change?
Recurring Savings: Frequently Asked Questions
Will I earn the full APY on a recurring savings plan?
Not on your total contributions. Because you add money gradually, the APY isn't applied to your whole balance for the full term, so the effective yield — after-tax interest as a share of your deposits — is lower than the headline APY, often roughly half over a multi-year plan.
Which is better, simple or compound interest?
At the same rate and term, compound interest returns more, because each month's interest is added to the balance and earns interest too. Everyday savings accounts often compound daily or monthly, while some fixed products use simple interest — check your account terms.
How is savings interest taxed?
Interest from a savings account or CD is taxed as ordinary income in the year it's credited and reported on Form 1099-INT (issued at $10 or more). There's no single flat rate; what you owe depends on your federal bracket and state. This tool uses a representative 22% for the "taxable" estimate.
How can savings grow tax-free?
In a tax-advantaged account such as a Roth IRA (qualified earnings are tax-free) or an HSA used for medical costs, growth can avoid tax. Choosing "tax-advantaged" sets the tax to zero here. Contribution limits and eligibility rules apply, so confirm the specifics for your account.
Why might my actual maturity value differ?
Real results vary with your bank's compounding method and rounding, any fees, whether a variable rate changes mid-term, and your personal tax situation. Treat this as a close estimate and confirm the exact figure with your institution.
What is effective yield?
Effective yield is the after-tax interest you earned as a percentage of your total deposits. Because a recurring plan doesn't apply the APY to your full balance for the whole term, comparing effective yield gives a more accurate picture across products.
What happens if I stop or withdraw early?
Stopping deposits simply ends further growth from that point. Withdrawing early from a fixed product like a CD usually triggers an early-withdrawal penalty of several months' interest. This tool assumes you keep contributing to maturity, so early withdrawal would leave you with less than the estimate.
Reviewed 2026-07-18. Interest from savings accounts and CDs is taxed as ordinary income (Form 1099-INT); there is no single flat rate. The "taxable" estimate uses a representative 22% marginal rate — your actual rate depends on your bracket and state.