| College year | Child's age | Years from now | Cost today | Inflated cost |
|---|
| Age | Phase | Contributed | Gains | Withdrawn | Ending balance |
|---|
Two ways to use this planner
Saving for college can be approached from either end. In "Tell me what to save" you fix the goal — the projected cost — and the planner solves for the monthly amount that reaches it. In "Start from what I can save" you fix the monthly amount to what your budget allows, and the planner shows how far that gets you. The first answers "what would it take?"; the second answers "where do I stand?" Both use exactly the same underlying math, just solved in opposite directions.
Why a gap is normal
Not every family can save the full cost of college in advance, and that is completely ordinary. When your saving covers part of the cost, the rest is simply a gap — the amount still to be funded another way. The most common way to bridge it is a college loan: money borrowed now and repaid later. A planned, well-understood loan is a normal part of paying for college, not a sign anything went wrong. A companion step will let you carry any gap shown here straight into a loan planner.
How the future cost of college is calculated
A year of college that costs $30,900 today will almost certainly cost more by the time your child enrolls, because prices tend to rise over time. To find the future cost, the planner takes today's number and grows it by the education-inflation rate for every year between now and the year that bill is due. The formula is today's cost multiplied by (1 + inflation) raised to the number of years away. At 3% inflation, a cost 15 years out is multiplied by roughly 1.56 — so $30,900 becomes about $48,100. (The $30,900 default is about the 2025–26 average total cost of attendance for in-state students at a public four-year college — $30,990 — per the College Board's Trends in College Pricing 2025.)
Why starting earlier lowers the monthly amount
The earlier you begin, the more months you have to spread the saving across, and the longer each dollar has to grow. Both effects pull the monthly amount down. A family with fifteen years to save needs far less per month than a family with five, even for the same goal — partly because there are three times as many payments, and partly because early dollars compound for much longer. Time is the most powerful lever on this page.
Why investment growth helps — but is uncertain
Investment gains are the growth the account earns on top of what you put in. They do real work: in the default example, gains cover a meaningful share of the total, money you never had to contribute yourself. But growth is not promised. Markets rise and fall, and the returns on this page are simplified assumptions, not guarantees. Treat the gains figure as an estimate of what might happen, not what will.
Why risk matters most near the spending date
When college is a decade away, a market dip has time to recover before you need the money. When college is a year away, it does not. This is why the same investment risk feels very different early versus late, and why the glide path — a gradual shift from growth-focused assumptions toward safer ones as freshman year nears — is the automatic default in most 529 plans. The planner models it with four stages you can edit; it is an illustration, not a recommendation.
Saving during college
Tuition is not due all at once. Because the junior and senior-year bills are still two and three years away when college begins, money saved during the early college years still has time to help. Turning on "Keep contributing during college" adds those later dollars and usually raises how much of the cost your saving covers.
Amount needed, contributions, gains, funded, gap, and surplus
The total projected cost is the inflated price of all four years — the goal. Contributions are what you put in: your starting balance plus every deposit. Investment gains are what the account earns on top. The amount your plan funds is how much of the cost your savings can actually cover; whatever is left is the gap. If your savings more than cover the cost, the leftover is a surplus — which can stay invested for more schooling like a master's or PhD, or move to a sibling's education.
Key takeaway
Whether you start from the costs or from your budget, the aim is the same: a clear, honest picture of how saving and growth stack up against the price of college. A gap is not a verdict — it is just the part to plan for next. This tool is an educational model, not investment or tax advice, and the returns it shows are assumptions worth questioning and adjusting.