Mortgage Payoff vs. College Savings: Which Comes First?

Two good goals, one paycheck. Here is the arithmetic that decides which one gets the money first.

What does $200 a month actually buy on each side?

Start with one loan and one number so nothing floats. Take a $320,000 mortgage at 6.5% on a 30-year term. Principal and interest come to $2,022.62 a month. Now add $200 a month of extra principal and hold it there.

Eighteen years later — the month the first tuition bill lands — here is where those dollars sit:

Where the $200 a month went	Value at year 18	Can you spend it on tuition?
Extra principal on the mortgage	Balance is about $120,200 instead of about $201,900 — roughly $81,700 of extra equity	No, not without borrowing it back
A 529 plan, assuming 6% growth	About $77,000, from $43,200 of contributions	Yes, tax-free for qualified costs

The mortgage column looks bigger, and over the full life of the loan it is: that same $200 a month saves about $105,000 of interest and retires the loan about 6 years 7 months early. But the two columns are not the same kind of money. One is a bill you no longer owe. The other is cash you can hand to a bursar. Run your own loan through the extra payment calculator before you assume the numbers above match your situation.

Why can't you spend home equity on tuition?

Because equity is not a balance you can draw on. It is the gap between what the house is worth and what you owe. Paying extra principal shrinks the debt side of that gap, and the only ways to turn it back into cash are to sell the house, refinance, or open a home equity line.

That matters more than most people expect. A family that put every spare dollar into the mortgage for 18 years can be genuinely wealthy on paper and still unable to cover a $12,500 tuition bill in September. This is the "house rich, cash poor" trap, and it hits hardest exactly when a dated expense arrives.

There is a second sting. Extra principal does not lower your monthly payment. It shortens the term instead. So the year your child starts college, your housing cost is exactly what it was the year before — you just have a shorter runway left. If you want a lower monthly payment from a lump sum, that is a recast question, not an extra-payment question.

Does home equity or a 529 hurt financial aid more?

This is the part that surprises people, and it usually points the other way from what they guess.

• Federal aid (FAFSA). The FAFSA does not ask for equity in your primary residence at all. Paying down your mortgage moves money into an asset the federal formula cannot see.
• A parent-owned 529. It counts as a parent asset. Parent assets are assessed at a maximum of 5.64% a year, so $77,000 in a 529 raises your expected contribution by roughly $4,300 — not $77,000.
• CSS Profile schools. A few hundred private colleges use their own form, and many of them do count home equity, often capped at some multiple of your income. At those schools the advantage flips.

So the aid angle nudges toward the mortgage, but weakly. A 5.64% assessment is not a penalty worth reorganizing your finances around, and a 529 keeps its federal tax-free growth on qualified education costs — the rules are laid out in the IRS 529 guidance. Talk to a CPA about how your own state's 529 deduction changes the arithmetic, because several states add a deduction that the federal picture above does not include.

What order should the money go in?

Ranked by what a dollar is worth in each slot, most families land on this order:

1. Employer retirement match. An instant 50–100% return beats a 6.5% mortgage and a 6% market assumption by a mile.
2. An emergency fund of three to six months of expenses. Without it, one furnace or one layoff undoes years of extra principal.
3. Any debt above your mortgage rate. Credit cards and unsecured loans are almost always the highest-rate dollar in the house.
4. The dated goal — college — up to the amount you honestly intend to pay. This is the one with a deadline you do not control.
5. Extra mortgage principal with what is left.

The mortgage sits last not because it is unimportant but because it is the only item on the list with a flexible deadline. You choose when to finish it. You do not choose when your child turns eighteen.

Does your child's age change the answer?

Yes, and it is the single biggest input. Time is what makes a 529 work, and it is also what makes extra principal work. Whoever has more of it wins.

Years until college	What $200 a month becomes in a 529 (6% assumed)	Reasonable lean
18 years	About $77,000 on $43,200 contributed	Fund the 529 first — compounding has room to work
10 years	About $32,800 on $24,000 contributed	Split it; the growth advantage is thinner
3 years or less	Roughly your contributions, minus market risk	Cash savings, not a 529 growth bet — and the mortgage is fine to keep feeding

With three years left, a 529 is mostly a tax wrapper on a savings account, and a guaranteed 6.5% from extra principal starts looking better than an uncertain 6% with no time to recover from a bad year. With eighteen years left, the reverse is true.

When does your mortgage rate settle the argument?

Extra principal is a guaranteed, after-tax return equal to your interest rate. That is the honest way to frame it, and it makes the comparison clean:

• Rate under about 4%. Hard to justify prepaying ahead of a college fund. A 3.25% guaranteed return is a low bar for an 18-year horizon.
• Rate between about 4% and 6%. Genuinely a coin flip. Split the money and stop agonizing.
• Rate above about 6.5%. Prepaying is competitive with any reasonable market assumption, and it carries no risk of being down 20% the year tuition is due.

One caution that applies at every rate: if you already itemize and deduct mortgage interest, your effective rate is lower than the number on your statement, which tilts the math toward the 529. If you take the standard deduction — most households do — your rate is your rate. We walked through the broader version of this trade-off in Should You Pay Off Your Mortgage or Invest?, and the college case is the same logic with a hard deadline bolted on.

How do you actually split the money?

Pick a number you can hold through a bad month, then automate both halves so neither depends on willpower:

1. Decide what share of college you intend to cover. Half? Four years at an in-state public? Write the number down. "As much as possible" is not a target you can fund.
2. Back into a monthly 529 contribution from that number and your years remaining. Set it to auto-draft on payday.
3. Send the remainder as extra principal — as a separate transfer, not a bigger regular payment.
4. Label the principal transfer "apply to principal." Servicers routinely park unlabeled extra money as a prepaid next installment instead. Check the following statement to confirm the balance dropped.
5. Re-run the split each January and after any raise. The right ratio at age 4 is the wrong one at age 14.

Most families find the split more durable than picking a side, because it removes the feeling that one goal is losing. Both lines move every month.

What do parents get wrong here?

• Skipping the retirement match to do either one. There are loans for college. There are none for retirement.
• Planning to tap home equity for tuition. You would be borrowing back money you already paid down, at whatever rate exists in that year, and converting a shrinking debt into a growing one.
• Overfunding a 529 for a child who wins a scholarship or skips college. Non-qualified withdrawals owe income tax plus a 10% penalty on earnings. Beneficiaries can be changed, which softens this — but plan for it rather than discovering it.
• Sending one big lump at the mortgage and then quitting. Consistency beats intensity. The canonical $105,000 figure above comes from $200 a month held for years, not from one heroic payment.
• Assuming extra principal lowers next month's payment. It does not. It shortens the term.

None of these require a spreadsheet to avoid. They require deciding, once, which goal has the deadline — and then funding that one first.

Frequently Asked Questions

Should I stop extra mortgage payments to fund a 529?

Usually you should reduce them rather than stop them. College has a fixed date and home equity cannot pay a tuition bill, so the dated goal is funded first. But keep a smaller extra-principal transfer running, because the habit is harder to restart than to maintain. If your rate is above about 6.5%, keep the larger share on the mortgage.

Does paying down my mortgage hurt my chances of financial aid?

Not for federal aid. The FAFSA does not ask about equity in your primary residence, so extra principal is invisible to that formula. A few hundred private colleges use the CSS Profile instead, and many of those do count home equity, often capped at a multiple of your income. Check which form your target schools require.

How much does a 529 reduce my financial aid?

A parent-owned 529 counts as a parent asset, and parent assets are assessed at a maximum of 5.64% per year. A balance of $77,000 raises your expected family contribution by roughly $4,300, not by the full balance. Student-owned assets are assessed far more heavily, which is why parent ownership is the common choice.

Can I use a HELOC to pay tuition instead of saving?

You can, but it undoes the work. You would be borrowing back principal you already paid down, at whatever rate exists in that year, turning a shrinking debt into a growing one secured by your house. It also adds a payment during the same years you are covering college costs. Treat it as a last resort, not a plan.

What if my child does not go to college?

You can change the 529 beneficiary to another qualifying family member, including yourself, without tax consequences. If you withdraw the money for something else, the earnings portion owes income tax plus a 10% penalty. Your contributions come back untaxed. Decide how much to fund with that possibility in mind.

Is it better to pay off the mortgage before my kids start college?

Only if the timing works without starving the college fund. Being mortgage-free at year 17 frees up your whole payment for tuition, which is powerful. Being mortgage-free at year 24 does nothing for a bill due at year 18. Map the payoff date against the first tuition date before committing to that plan.