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)
Washington example — $$14,908/year at 7%:
- After 10 years: $205,976 ($149,080 contributed)
- After 20 years: $611,161 ($298,160 contributed)
- After 30 years: $1,408,221 ($447,240 contributed + $960,981 gains)