The growth check is the compound-interest check
Ten thousand dollars, no monthly addition, 5 percent a year, compounded monthly for 10 years, ends at $16,470.09. That is the same known answer as the compound-interest page. The unrounded monthly compound is the formula Investor.gov's compound-interest calculator uses, and this site rounds the ending balance to the cent. The 5 percent is not a historical return on any 529 plan, any mutual fund, or any year of college inflation. Replace it and the ending balance changes. A rate of zero with no additions leaves the balance where it started. The page will not substitute a "college inflation" rate, because no such rate was verified for this calculator.
Contributions are treated as end-of-month deposits, the same convention as the compound page. A family that contributes on the first of the month earns a few extra days of the assumed return. This page does not model that. It also does not subtract plan fees. A fee you do not type stays in the projection. The years box is how long you want the assumption to run, not a child's age and not a graduation date.
The $19,000 exclusion is a gift-tax line
Section 4.42 of Revenue Procedure 2025-32 says that for calendar year 2026, the first $19,000 of gifts to any person, other than gifts of future interests in property, is not included in taxable gifts. The IRS estate-and-gift "what's new" table lists $19,000 for both 2025 and 2026. This page uses $19,000.00. A contribution to a 529 plan can be a gift to the beneficiary. The page does not decide that it is. It takes the monthly addition, multiplies by 12, and splits that annual amount at $19,000.
Two thousand dollars a month is $24,000 a year. Of that, $19,000.00 is inside the exclusion and $5,000.00 is above it. The form's default monthly addition is $0, so the exclusion lines on the first load are zero. The $2,000 case is the check, not the opening balance. Amounts above $19,000 are not blocked. The exclusion is not a maximum contribution. Crossing it can mean a taxable gift, a gift-tax return, or the use of lifetime exclusion, none of which this page computes. Gifts of future interests are outside the sentence in the revenue procedure, and this page cannot tell a future interest from a present one.
The five-year election is not applied
Gift-tax law lets a person elect to treat a 529 contribution as if it were spread over five years, within limits. This page does not apply that election. It does not ask whether you already made the election, whether a spouse is splitting gifts, or whether you gave the same person anything else this year. The $19,000 line is one donor, one person, one calendar year, and only the additions you typed. Other gifts to that person — cash, a car, tuition paid a different way — would use the same exclusion. They are invisible here. Two donors, such as two parents, can each have an exclusion. The page does not double $19,000 unless you decide you are looking at one donor's additions only, which is all the box can see.
A year of additions is the monthly amount times 12, even if you stop after six months. If you will not contribute every month, lower the monthly figure or treat the result as a full year you do not actually plan. The exclusion comparison is not a forecast of the account. It is a split of the annualized contribution.
What the projection refuses to decide
Earnings in a 529 plan can be untaxed when they are used for qualified education expenses, and they can be taxed, sometimes with an additional tax, when they are not. This page does not identify a qualified expense, a school, a room-and-board limit, a K-12 withdrawal, or an apprenticeship. It does not quote a tax rate on a nonqualified withdrawal. Writing those rules from memory would be exactly the kind of unsourced figure this site is not willing to print. The balance at the end of the projection is a compounded assumption. It is not an after-tax balance and it is not a financial-aid figure. Aid formulas can count a parent-owned plan differently from a student-owned plan. That difference is not modeled.
State tax deductions or credits for 529 contributions are also omitted. They depend on the state and on whether the plan is the state's own. No state rule was added here. The Roth IRA limit page is a different account with its own 2026 ceiling. A rollover from a 529 plan to a Roth IRA, which the law allows only in specific cases, is not computed. The retirement projection is wages and a workplace or IRA contribution, not tuition.
Giuseppe Ilarda, the site owner, writes and checks the compound balance and the $19,000 split. The disclaimer applies. Choosing a plan, an investment inside the plan, or a beneficiary is not a result of this arithmetic. If the assumed rate is wrong, the ending balance is wrong with it. The exclusion line does not depend on that rate. It depends on how much you add this year.