529 Calculator

Projected 529 balance at age 18

$48,837

Total$48,837
Years until college
13 years
Total contributions
$31,200
Investment growth
$17,637
New York deduction cap per year
$5,000
Estimated state tax saved over 13 years
$0

State tax saving uses New York's top marginal rate of 0% applied to the deductible portion of your contributions.

Plan: NY 529 Direct Plan (Vanguard). Minimum contribution $25, maximum account balance $520,000.

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What this result is based on

This tool uses only the figures you enter and standard arithmetic. No external dataset feeds the result, so there is nothing to cite beyond the formula shown on the page.

This 529 calculator compounds your starting balance and ongoing contributions at the rate of return you choose, then splits the ending figure between what you contributed and what the market added.

Compounding rewards time far more than timing, which the year-by-year table makes obvious.

Frequently asked questions

A diversified stock portfolio has historically returned roughly 7% a year after inflation over long periods, but any single decade can be far higher or lower. Model a low, expected and high case.

Balance college saving against your own retirement

Funding a 529 too aggressively can cost you more in lost retirement compounding than it saves in tuition. An advisor prices the trade-off.

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The short answer

A 529 plan grows tax-free when the money is spent on qualified education costs, and more than 30 states add a state income tax deduction or credit for contributions. Enter your child's age and monthly contribution to project the balance at 18 and the state tax you would save along the way.

Methodology

The research behind this calculator

529 Calculator This tool uses only the figures you enter and standard arithmetic. No external dataset feeds the result, so there is nothing to cite beyond the formula shown on the page.

What a 529 plan does

  • Investments grow federally tax-free and withdrawals for qualified education costs are untaxed.

  • Qualified costs include tuition, fees, books, computers, and room and board for enrolled students.

  • Up to $10,000 a year can go to K-12 tuition, and $10,000 lifetime to student loan repayment.

  • Unused funds can be rolled to a sibling, or up to $35,000 into the beneficiary's Roth IRA subject to conditions.

The state tax deduction is the difference

New York gives a $5,000 deduction for single filers and $10,000 for joint filers. Pennsylvania allows a deduction up to the federal gift tax exclusion, and Indiana gives a 20% tax credit rather than a deduction.

The formula

FV = B(1 + r/12)^(12t) + C × [((1 + r/12)^(12t) − 1) ÷ (r/12)]. State saving = min(annual contribution, deduction cap) × state marginal rate.

FAQ

Marginal rate versus effective rate

Two numbers describe your tax position and they are almost never the same. The marginal rate is the rate applied to your next dollar of income — it is the number that decides whether an extra shift, a bonus or a side contract is worth taking. The effective rate is total tax divided by total income, and it is always lower, because the early slices of your income were taxed at 10% and 12% no matter how much you went on to earn.

The practical consequence is that crossing into a higher bracket cannot reduce your take-home pay. A single filer who earns one dollar more than the 22% threshold pays 22 cents on that dollar and nothing changes underneath it. Advice built on the opposite belief — turning down a raise, refusing overtime near year end — costs real money.

Use the marginal rate when you value a deduction: a $1,000 deductible contribution is worth $220 to someone in the 22% band and $370 to someone at 37%. Use the effective rate when you compare years, budget for an annual bill, or judge whether a move across state lines actually improved your position.

Where withholding goes wrong

Most people never calculate their own tax; their employer estimates it every payday from the Form W-4 on file. That estimate assumes the job in front of it is your only source of income and that your circumstances have not changed since you signed the form. Both assumptions break quietly.

The classic failure is a second income. Two jobs each withhold as though their salary were the whole picture, so both apply the standard deduction and both start you at the bottom of the bracket ladder. The combined return then lands with a balance due. The fix is the multiple-jobs step on the W-4, or a fixed extra amount withheld each period.

The mirror image is the large refund. It feels like a windfall, but it is money you lent the Treasury at zero interest for up to sixteen months. Reducing withholding so the return lands within a few hundred dollars of zero puts that cash in your own account, where it can sit in a savings product that actually pays.

Check withholding after any of the following: a raise, a bonus, a marriage or divorce, a new child, a house purchase, a change in dependants, the start or end of a second job, or a spouse returning to work.

The deductions and credits worth chasing

A deduction lowers the income that gets taxed; a credit lowers the tax itself. That difference is enormous. A $2,000 deduction saves a 22% filer $440. A $2,000 credit saves them $2,000. Prioritise credits, and check refundability — a refundable credit pays out even when it takes your liability below zero.

On the deduction side, the decision is binary: take the standard deduction, or itemise. Itemising only wins when mortgage interest, state and local taxes up to the statutory cap, charitable gifts and qualifying medical costs together exceed the standard amount. Bunching two years of charitable giving into one calendar year is the usual way to make that arithmetic work.

Above-the-line reductions sit outside that choice and are available whether you itemise or not: traditional 401(k) and traditional IRA contributions, health savings account deposits, the deductible half of self-employment tax, and student loan interest within the income limits. These are the levers most households still have unused in December.

Why the same salary is worth different amounts in different states

Federal rules are national. Everything below them is not. Nine states levy no broad tax on wage income; others run graduated schedules with top rates above 10%. But income tax is only the visible part. Property tax funds local services and varies by more than a factor of five between the cheapest and most expensive states. Combined sales tax adds up to double digits in some jurisdictions once local surcharges are counted, and it falls hardest on households that spend most of what they earn.

Insurance is the charge that has moved fastest. Home premiums have risen sharply in states exposed to wind, wildfire and hail, and in several markets the premium now rivals the property tax bill. A no-income-tax state with high property tax and high premiums can leave a middle income household worse off than a moderate income tax state next door.

That is why every calculator here has a version for all fifty states plus the District of Columbia, each carrying its own schedule, deduction, exemption and local charges. Pick your state below rather than reading a national average as though it were your answer.

The bottom line

Run the numbers with your real figures rather than round ones: the difference between an estimate and your actual position is usually the detail you rounded away.

Change one input at a time to see which lever moves the result most, and act on that lever first.

Treat the output as a planning estimate. Rates, thresholds and local charges change every year, and no calculator knows your full circumstances.

Find a financial advisor near you

A calculator settles the arithmetic. Sequencing a pension, a house purchase and a tax bill against each other is judgement, and that is where a fiduciary adviser earns their fee. Our adviser pages explain what the different fee models cost, what questions separate a planner from a salesperson, and how to check any adviser against the official registers before you share a single figure.

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Revision history

No revision has been recorded for this page since we started versioning content. The published version is the first stored version.

Think a figure is wrong? Read our corrections policy and report it. We correct on the page itself and log the change here.

Read the full guideInvesting Guide

How we built this calculator

Content and methodology updated
Written and maintained by
Think Bigger Today editorial team

What the result rests on

This tool uses only the figures you enter and standard arithmetic. No external dataset feeds the result, so there is nothing to cite beyond the formula shown on the page.

We do not claim to be licensed advisers and we publish no anonymous expert reviews. What we do commit to is method: where a figure comes from an ingested dataset we name that source and show when it was observed, and where we cannot verify it we leave it out. See how we source our data.