Windfall Allocation Calculator

Follow a priority order: first clear high-interest debt, since paying off a 22% card is a guaranteed 22% return; next build an emergency fund of three to six months' expenses; then invest the rest. Beyond that, larger sums may go to a mortgage, education, or goals — but the first three steps come in order.

Because paying off debt earns a guaranteed return equal to its interest rate, with no risk. Clearing a 22% credit card is a certain 22% — far better than the roughly 7% an investment might average, and without the volatility. High-interest debt beats investing almost every time.

Three to six months of essential expenses for most people, more if your income is variable or your job is less secure. A windfall is a rare chance to fund it in one move rather than scraping it together monthly. It is what keeps the next surprise from becoming new high-interest debt.

For the portion earmarked to invest, lump-sum investing has historically beaten spreading it out, simply because markets rise more often than they fall. Spreading it over a few months can ease the psychological risk of buying right before a dip, at a small expected cost. Either is fine; not investing it is the real mistake.

Treat it like one for allocation, but remember it is your own money that was over-withheld — an interest-free loan to the government. If you get a large refund every year, adjusting your W-4 puts that money in your pocket during the year instead, where it can work for you sooner.