Should You Spend, Save, or Invest Your Bonus — and in What Split?

A windfall without a plan becomes lifestyle inflation within six months. Most people deposit their bonus, make a few impulsive purchases, and find themselves wondering where it went by spring. The difference between a bonus that changes your financial trajectory and one that disappears is entirely in the allocation decision made in the first 72 hours. The optimal bonus split depends on four factors: your debt interest rates, the size of your emergency fund, your tax-advantaged account headroom, and how much you can realistically direct to long-term investing without feeling deprived. Getting even one of these wrong — especially ignoring high-interest debt in favor of investing — can cost thousands of dollars in avoidable interest. This calculator builds a personalized allocation plan for your specific bonus amount and financial situation. It prioritizes high-interest debt payoff first (because paying 20% credit card interest is a guaranteed 20% return), then emergency fund gaps, then investing in tax-advantaged order, then liquid savings, and finally intentional spending. The result is a complete action plan with projected 20-year wealth impact — not a generic "save more" recommendation, but a specific dollar split you can execute immediately after reading.