What this calculator does
Find out how much to save each month so college is paid for when your child gets there. College bills come years from now, in dollars that will buy less than today's. So a plan needs two answers: what college will cost by then, and how much regular saving it takes to get there.
This calculator gives you both. It grows today's yearly cost at the rate you expect college prices to rise, then adds up every year of study. Next it counts what you've already saved and the return you expect. Then it works out the monthly amount that would cover the share of the cost you choose.
It works for any college fund you keep for the purpose, such as a 529 plan, an education savings account or an ordinary investment account. Money you haven't spent yet keeps earning a return during the college years. So you don't need the full total saved on the first day. You only need the present value of the later bills: what they're worth on that day, allowing for the return still to come.
Where it's used
Why this math matters outside the classroom:
- Planning for a newborn. Parents estimate that $25,000 a year today becomes about $60,000 a year in 18 years if costs rise 5% a year.
- Grandparents' gifts. A grandparent checks how much a $5,000 gift today could grow to by the time a grandchild starts college.
- Comparing schools. A family compares the monthly saving needed for an in-state public school with a private college.
- Personal finance classes. Students use the geometric series formula to find the monthly deposit that reaches a set amount in 13 years.
- Workplace benefits. An employee sets a payroll deduction into a college savings plan based on the projected gap.
Grade level and standards: Grades 11–12; Common Core State Standards for Mathematics HSA.SSE.B.4. © Copyright 2010. National Governors Association Center for Best Practices and Council of Chief State School Officers. All rights reserved.
How to use it
- Enter your child's age now, the age college starts and the number of years of study.
- Enter the yearly cost at today's prices, and how fast you expect college costs to rise each year.
- Enter what you've already saved, the average yearly return you expect, and the share of the cost you want savings to cover.
- Read the monthly saving needed and the projected cost. Then check the yearly table to watch the balance build until college starts.
What the inputs mean
- Cost per year in today's dollars
- The full yearly cost you plan to pay, at today's prices. That's tuition and fees, plus housing, food and books if you plan to cover them. School websites publish current figures.
- Yearly increase in college costs
- How quickly you expect college costs to grow each year. College prices have often risen faster than general inflation. So a rate a bit above inflation is a cautious choice.
- Expected annual return on savings
- An average yearly return after fees. Many college plans shift toward safer investments as the start date gets closer, which lowers the average.
- Share of the cost to cover from savings
- Many families plan to cover part of the cost from savings, and the rest from current income, aid or loans. Enter 100 to cover all of it.
Formula and method
years to go: t = college start age − child's age bill for college year k: B_k = C × (1 + g)^(t + k), for k = 0 … Y − 1 needed at college start: N = share × Σ B_k ÷ (1 + r)^k monthly rate: i = (1 + r)^(1/12) − 1 monthly saving: M = (N − S × (1 + i)^(12t)) ÷ (((1 + i)^(12t) − 1) ÷ i)
Here t is the years until college. C is today's yearly cost, g the yearly cost increase and Y the years of study. k counts the college years, starting from 0 for the first. B_k is the bill for year k. r is the yearly return and i the matching monthly return. S is what you've already saved, N is what you need on the first day of college and M is the monthly saving. Σ means 'add up'.
Each year's bill is today's cost, grown for the years until it's paid. It's due at the start of that college year.
Bills after the first are discounted (shrunk) back to the first day of college at the return rate. That's because the money set aside for them stays invested until it's needed. Your current savings grow on their own. The gap between them and the amount needed is divided by what $1 saved at the end of every month grows to. That gives the monthly amount.
Worked example
Your child is 5, college starts at 18 and lasts 4 years. It costs $25,000 a year today, costs rise 5% a year, you have $10,000 saved, and you expect a 6% return.
- Years until college: 18 − 5 = 13, so you have 156 months to save.
- First-year cost: $25,000 × 1.05¹³ = $47,141.23. The four years total $203,184.59.
- Discounting the later years to the start of college at 6% gives $185,913.29 needed on day one.
- Your $10,000 grows to $10,000 × 1.06¹³ = $21,329.28.
- The gap of $164,584.01, divided by what $1 a month grows to in 156 months, gives about $707.12 a month.
Result: Saving about $707.12 a month would cover the projected $203,184.59 cost; you'd put in about $110,311.37 of it yourself.
Understanding the result
The monthly figure is what it would take to pay for the share you chose entirely from savings. If it's more than you can manage, you have the same options as for any goal. You can start sooner, cover a smaller share or plan on a lower-cost school. Or you can count on a higher return, which brings more risk.
Starting early matters a great deal. The balance has longer to grow, with earnings building on earnings. So the first few years of saving do more of the work than the last few. Try the calculator with your child's age a few years higher. You'll see how quickly the monthly amount rises.
Assumptions and limitations
- Costs rise at a steady yearly rate, and each year's bill is paid at the start of that college year.
- Savings earn a steady average return, both before and during college. Deposits go in at the end of each month until college starts.
- There are no taxes, no account fees beyond those built into the return, no financial aid or scholarships, and no withdrawals before college.
- Real costs and returns change from year to year. The result is a planning estimate, not a guarantee.
- It doesn't model the tax treatment and rules for 529 plans and other accounts, or their effect on financial aid.
- This is general education, not financial advice.
Frequently asked questions
How much should I assume college costs will rise?
Use a rate a little above what you expect for general inflation, since college prices have often grown faster than prices overall. Try a low and a high rate to see the range. Over 15 years, a couple of percentage points can change the projected total by tens of thousands of dollars.
Why is the amount needed at the start lower than the total cost?
Only the first year's bill is due on the first day. Money set aside for the later years stays invested and keeps earning a return until it's spent. So you need a little less than the full total on the first day of college.
Does this work for a 529 plan?
Yes. Enter the plan's current balance as your savings, and the average return you expect from its investments. The calculator doesn't model the plan's tax benefits, state deductions or withdrawal rules, which vary by state and plan.
What if I only want to cover tuition, or half the cost?
Enter just the costs you plan to pay as the yearly cost. Or keep the full cost and set the share to cover from savings, for example 50%. Either way, the monthly amount drops in proportion.
How this calculator is checked
Method: Cost projection by compound growth; present value of the college bills at the start date; future value of current savings and of an ordinary monthly annuity at the effective monthly rate, solved for the payment. The calculation is covered by automated tests with known reference values and edge cases. Last updated 2026-10-18. Found a problem? Tell us.
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