How much should I contribute each month?
Working backwards from the bill instead of forwards from a guess. Full funding is one option among several — covering part of the cost on purpose is a legitimate plan.
Nothing calculated yet
Fill in your situation above, then press Run the numbers to see your four paths.
Working backwards instead of forwards
Most contribution calculators run forwards: you guess a monthly figure and they show where it lands. That tells you about the guess, not about the goal. This tool runs the other way — it starts from the projected bill and solves for the monthly amount that reaches it under your assumptions.
The number it returns is a consequence of four inputs: the cost you are aiming at, the years available, the balance you already have, and the return you assume. Change any of them and the monthly figure moves, sometimes sharply.
Full funding is one target among several
The tool defaults to covering the whole projected cost because that is the question people ask, but it is not the only defensible target. Half the cost, four years of in-state public rather than private, or a fixed sum you are comfortable committing are all coherent goals, and the tool will solve for any of them.
A monthly figure that is out of reach is useful information rather than a failure. It means the target, the horizon or the school assumption needs revisiting — and revisiting it now is considerably cheaper than discovering the gap later.
Why starting earlier changes the number so much
Contributions compound for the time that remains after they are made, so an early contribution earns for years and a late one barely at all. The required monthly figure therefore rises much faster than the shortening horizon suggests: halving the time available more than doubles the monthly amount needed to reach the same target.
Common questions
- How much should I put in a 529 each month?
There is no general answer, because the figure depends entirely on your target, your horizon and what you already hold. The tool computes it from those inputs. What it cannot weigh is the rest of your finances — a contribution that reaches the target but crowds out retirement saving or an emergency fund is a trade-off the tool cannot see.
- Should I fund the 529 before my retirement accounts?
That is a personal financial planning question rather than a calculation, and it is outside what this site does. It is worth raising with a qualified adviser, who can weigh your full position — something no calculator, including this one, has sight of.
- Does contributing a lump sum beat contributing monthly?
Under a fixed assumed return, money invested earlier compounds for longer, so a lump sum placed today produces more than the same total contributed over the following years. The tool models start-of-month contributions and shows the effect of your existing balance separately, so you can compare the two.
Same numbers, different question
- Should I stop contributing to my 529?Compare all four contribution paths at once
- Am I on track?See your funding ratio and what would close the gap
- Am I putting too much into my 529?Check whether your current path overshoots
- How should I split savings between my children?Work out the split that levels your children up
- I have leftover 529 money. Now what?Rank the reuse, rollover and withdrawal pathways
- 529 or a brokerage account?Weigh the 529 tax advantage against keeping your options open
Your numbers carry across. They stay in this browser tab and are never sent anywhere.