Investment Return Formulas
Total return on a lump sum:
FV = PV × (1 + r)^t
PV = initial investment | r = annual return | t = years
CAGR (Compound Annual Growth Rate):
CAGR = (Ending Value ÷ Beginning Value)^(1 ÷ Years) − 1
With annual contributions:
FV = PMT × [(1 + r)^t − 1] ÷ r
PMT = annual contribution (end of year)
Indiana example — $$10,794/year at 7%:
- After 10 years: $149,135 ($107,940 contributed)
- After 20 years: $442,505 ($215,880 contributed)
- After 30 years: $1,019,610 ($323,820 contributed + $695,790 gains)
Tax note for Indiana investors: In a taxable brokerage account, investment gains are subject to 2.95% state income tax plus federal capital gains tax (~15% for long-term). Combined rate ≈17.95%, reducing an effective 7% return to approximately 5.7% after tax. Tax-advantaged accounts avoid this drag entirely — use them first.