Reverse-engineering any financial goal
Pick the target dollar amount, the date you need it, and an expected return. The calculator solves for the monthly contribution required. The same math works for retirement, a house down payment, a wedding, or a child's college fund.
Goal-based asset allocation
Match risk to horizon. Money needed in less than 3 years should sit in cash/short bonds. 3–10 years: balanced 60/40. 10+ years: equity-heavy 80/20 or 100% equities. As the goal date approaches, glide toward safer assets to lock in gains.
The 4% rule and FIRE
Financial Independence, Retire Early (FIRE) typically targets 25× annual expenses, based on the Trinity Study's finding that 4% annual withdrawals from a 60/40 portfolio historically lasted 30+ years. Conservative variants use 3.5% (≈ 28× expenses) for longer retirements or higher safety margins.